lol, @ "right the way through to a big sounding megadeth type sound" - man you crack me up with that!
All of the BKPs are very well-made. You'll be able to get very good cleans from all of them, although in some cases you might have to roll back a touch on the volume. That said, I use a miracle man (pretty high output), and it's got a cracking clean sound when I want it to sound like that. If you were to get an AlNiCo V warpig, the cleans will be 'better' than, say, a ceramic pig (and possibly better than my [ceramic] miracle man, but I can't confirm that without first-hand experience).
Basically: Stop worrying about the BKPs. Just go for whatever Tim suggests once you've settled on the guitar you want, and if you're not happy (heh, extremely unlikely), you've got a cool-off period anyway, and you'll be able to swap them for something else.
Roo