I’m 6’6″, around 17 stone and have recently purchased a Bottlerocket. I’ve done a fair amount of riding on it so far and I’ve noticed the shorter top tube length, but not overly so – my other bike is an XL Chameleon.
I wouldn’t want to do an all day ride, with masses of ups on the Bottlerocket – but from what you describe above, it doesn’t sound as though that’s your plan either.
Surf Sales, the distributor for Transition in this country were fantastically helpful in organising a demo Bottlerocket for me, I ended up having it for about a week – do give them a call if you’re considering one. During my demo, I took it to the Surrey Hills for an all day session, a couple of sessions at Woburn and on a couple of my normal routes around home – hope that gives you some idea at least of the terrain I’ve based the above opinion on.