Experimenting with brakes like this would terrify me, locking up the front wheel at any speed can cause serious injury, it was brought home to me when one of my vans failed an MOT test by the local main Vauxhall dealer, Pedestal garage, High Wycombe, they talked me into letting them replace the rear brake shoes, I think they must have let a lad on work experience do the work as when I collected the van it soon became apparent that something was very seriously wrong, driving along there would suddenly be a loud bang followed by the rear wheels locking up solid and rear of the van squatting down momentarily before sorting itself out and then doing it again soon after, several times, it turns out the wrong length pull off springs had been fitted, and they were not pulling the brake shoes off, this experience made me aware of the power of the humble single leading brake shoe when left to servo uncontrolled, now I have no idea how this correlates to fiddling with the standard Vincent brakes, but fully floating sounds a bit like self servoing to me, not sure that I would want to risk it, I think for me it is either standard brakes, Vincent Speet brakes, or a disc conversion.