Anyone ride on tubs regularly?

Visiting friends next weekend in London and bringing my track bike with me to do the Saturday session at Herne Hill. I'll be riding across London on tubs (Conti Sprinters) and worried (hopefully needlessly so) about puncturing. I'll bring an old tub and some tape in case the worst happens. Couple of questions :-

Best method for folding a tub so I can stow it under my Brooks with a toe strap ?

Anyone had experience with Vittoria Pit Stop ? I'd like to have a go at repairing a tub puncture at some point, would using this make the tub un-repairable ?

Which London bike shops have a good tub selection ? If the worst happens I might treat might myself to one of the new 320tpi Vittoria CX's

I run a sprinter up front and its fine. on the rear depends how heavy you are as well as what pressure you're running them at.

I would bring a new (not old!) tyre or two and some tape. tis hard to get tubs over the counter in london. And maybe take rik's number and grab those tubs off him.

pit stop and that sort of stuff wont make the tub unrepairable unless you use boatloads to fix a tear, in which case you'd need to replace the tube anyway.
if you use glue normally then glue the tub and when it's dry fold it so it's glued side in. put it in a bag (i use one of those plastic tool holders that fit in a bottle cage) - you don't need grime and grit on the surface. And tufo tape is superb imo, much easier and very strong if you use it properly.