It's all about 2 bolt boosters.
They're easier to set up.
I modified my tensile booster, tarty say it's the stiffest 4 bolt booster you can get.
For the sake of ease I used to just run the top two bolts. I cut the bottom off later cause it makes it easier.
Anyway, yeah, unless your frame is ridiculously flexy - my ciguena for example used to flex out at pretty much the same rate as you'd pull the lever - get a 2 bolt booster.