'Coupla thoughts:
- you probably don't need hold downs on the router & saw - the forces on them are pretty small
- you only need 2 hold downs on the brake - to keep the front from lifting
- you do NOT want to use bolts of any kind - you do not want to be screwing & unscrewing bolts every time you use it. You want to move it into place, lock it down with MINIMAL motion & get to using it.
I would do something like this: have a plate in the floor with a keyhole opening (a circle with a smaller tail). On your brake you have a bolt whose head fits through the keyhole circle & whose shank fits the tail. You move the brake over the floor plate, lower the bolt through the keyhole, slide it slightly into the tail, & tighten the bolt. NOT by running a nut on its threads, but with a pull toggle clamp, like this:
formatting link
One flip of the lever tightens you down & another flip releases.
That's how I would do it, Bob