Well, I'm trying to come up with a realistic line-up. An AFD-era reunion is a fantasy; it just isn't going to happen. No promoter is going to take a chance on a tour that includes Axl (whose reputation for late starts precedes him), Izzy (who may at any time decide to wander off to find himself in Tibet) and Adler (a flaky ex-junkie who could fall off the wagon at any time). Hell, IIRC Izzy didn't show up to a couple of the Vegas shows he was supposed to be appearing at.

Bluntly: no-one but the hardcore fans care who the drummer and the rhythm guitarist are; not least because those two roles were already swapped out at the height of GN'R's fame. The casual public trade in icons; they will call it a reunion if Axl, Slash and Duff are up there; and even Duff isn't really essential to the vast mooing herd that will be buying tickets.

Axl's crafted a well-oiled touring machine over the last few years, one that operates at the scale a reunited GN'R would expect to play at. Slash plays small venues like the Hammersmith Apollo; while Axl's playing arenas, which are closer in scale to the stadiums that a GN'R reunion tour would be playing. So you have to think of it in terms of Slash, Duff and possibly Matt "plugging into" Axl's existing tour setup (as, indeed, Duff has already done). Axl has a tight, proven rhythm section in Frank and Fortus. They've worked with Duff before, too. So why would you take a chance on Gilby – a touring guitarist who did a stint with the band 20 years ago – and Matt? And even in this new era of thawed relations, Axl would probably want the majority of the band to be "his guys". Dizzy, well he's been there since the UYI days, and fits into the framework of a reunion. Pitman might as well be there, especially if you're looking to a future of writing new material; he's one of the key songwriters of the new band, and I suspect Axl would be more comfortable having him around. It suggests that any writing would be forward-looking, rather than just slapping some half-arsed vocals on generic rock riffs from Slash.

The hardcore fans can be catered for with crowd-pleasing guest appearances from Izzy and Adler, and maybe Matt and Gilby (in the manner of Bill Wyman and Mick Taylor on the recent Rolling Stones tour). I'll note that I was at the O2 gig where Izzy turned up, and half the crowd members around me – the people who'd been loudly parroting the line that "Axl broke up the original band, man, and it's not the same without Slash" – had no clue who he was.

It's not that bad. If you're compiling a Greatest Hits CD, you've got a couple of complicating factors. Firstly, and most importantly, you don't want to overload it with tracks from one album – otherwise the question people will ask is, "Well, why don't I just buy Appetite for Destruction, if 90% of the tracks are from it?" Then you've got to put something on there to entice fans of the band – ideally a new track. If you can round up the band members to record something new, that's ideal; otherwise you'll need to dig up an old B-side or unused track from the archive.

With that in mind – and bearing in mind that Axl was dead set against the idea from the start, not wanting to draw attention to the old band on the eve of his comeback with a new line-up – you're a bit limited in your options. Your "new track" is going to have to be something you have easy access to, and something that could reasonably sit on a Greatest Hits collection (so, not Shadow of Your Love...). If you can tout it as an EXCLUSIVE NEVER-BEFORE HEARD TRACK, so much the better. So you end up with Sympathy for the Devil, which you can at least bill as "never previously included on an official GN'R release." Which is like saying your film is "from the studio that brought you..."

So, Sympathy for the Devil is your "new" track. And you want a spread of material from AFD, UYI and Lies – and, really, you ought to stick something from TSI on there too so that you can bill it as a representative spread of the band's history.

With that in mind, there are certain non-negotiable tracks that have to be on there: SCOM, WTTJ and PC are the three everyone knows from AFD. Patience is the only one worth including from Lies, and YCBM, November Rain and Civil War have to be on there from the Illusions. Live and Let Die and KOHD are famous staples of the live set, so they're likely to make the cut, and Don't Cry and Yesterdays were singles. That leaves you with the TSI tracks; you really need something on there from TSI, so you can call it a representative overview of the band's history – Ain't It Fun is probably the best track on there, and Since I Don't Have You was (bizarrely) the single. It does leave you with the odd situation of a 14-track Greatest Hits album that's got five covers on it, but... well, the band should've made more fucking original albums before imploding, shouldn't it?

A lot of fans whinge that Estranged didn't make the cut, or It's So Easy or Nightrain – but put those tracks on there and you'll probably nudge up against the recommended 78 minute limit on an audio CD, or skew the balance too heavily towards AFD. And Axl's plan for a two-CD set was a bit daft, really – two CDs for a band that only put out three original albums, an EP and a covers disc?

I think it's probably the best they could've managed in the circumstances.

Realistically, I'd expect a "reunion" line-up to consist of:

Axl
Slash
Duff
Fortus
Dizzy
Pitman
Ferrer (maybe Sorum, depending on whether the Axl or Slash camp is running the show)

With Izzy, Adler and maybe Gilby dropping in for odd live performances. Reasons? I'd expect them to want to record at least some new material, whether that's a new album or a few new tracks tacked onto a Greatest Hits album. History's shown that Izzy isn't exactly reliable when it comes to touring, and Axl didn't consider Gilby good enough to record the follow-up to UYI back in the 90s, so why would that have changed? Dizzy and Pitman... well, why not? Might as well keep 'em in the mix.

And on a more practical level, both Ashba and Bumblefoot have left, but Fortus still appears to be in the band – he's a reliable rhythm player, can step up to shred the Buckethead parts in the unlikely event that the band is playing Chinese Democracy material, and Axl's referred to him as the band's "secret weapon". I'd say he's far more likely to be in the mix than Gilby.

The one Axl sent to the Rock N' Roll Hall of Fame: