I have the same outhaul system that Faster shows. I have a 26 ft C&C and the 4:1 outhaul is easily adjusted, so I expect it would be fine for your 27 footer.
I don't know this for sure, but I would have thought that a Bristol 27 would have a black band around the aft end of the boom to show the class length for the mainsail foot. This should tell you if the sail is too long in the foot.
Keep the outhaul control in the cockpit - it is an essential sail trim device and will be a pain if you have to go the mast every time you need to alter it.
(I once met a sailor in a race who told me he'd never moved his outhaul since he bought the boat. He didn't win much!)
Just because you're paranoid ...doesn't mean they're not after you!