So, now I can provide some numbers of my last setup for the Brampton fork: I added a rotary encoder from the shelf, funny 0.09 degrees resolution on the small black box in the photo, plus a tiny linear encoder, max stroke 11mm and read 66 degrees from lock to lock, 33 degrees one side. At straight ahead steering one degree rotation of steering produces 1.05mm stroke on the damper rod and close to the locks that reduces to 0.80mm due to lever effects, shown on the DRO.
I did another alu lever 3.0 in a lazy hour with 60 mm between centres because I could see a bit more stroke available , 64 from a total of 70mm in the China kit, plus a little more space by setting the cylinder with its offset bracket another few mm back towards the engine and is now fairly close to the sidecar lug. The old friction set had its anchor pin at 53mm , our starting size alu lever 1.0 . When turning the Bramptons to their locks you get about 7 mm clearance at the flanges that mate with the friction discs, and the rod, good enough for me. No need for extra safety clearances as the fork stops are very solid cast steel items - and even a damaged damper replaced at € 30.- from China is just peanuts - in the Vincent world today.
In most cases I do not see the need for extra bolts to fix the alu lever to the Brampton but one can add them certainly so as not to rely only on the friction discs. There are no existing bolt holes on that fork that could be used for the lever. The opinion seems to be that hydraulics are no real necessity on Bramptons and most drivers are comfortable with only light friction settings and that is why I just guess nipping up the standard friction plates via knob will lock the alu lever hard enough to do its job. But a countersunk screw there will ease your mind and when added you do not have to think of resetting ever later.
When going for my setup and a crash bar is fitted you will fabricate a bracket that is clamped on the bar. For a batch of sets one could provide a bracket with a clamping diameter large enough for biggest bars in use and supply split adapter bushes like with tele clip-ons or have the owner do his own split bushes, easy enough to do.
As to tank slappers, I looked into some web pages dealing with those. It seems you can expect them to hit you by pulling off high speed wheelies and when the front rubber touches down in minimal deflection to the basic direction you will be challenged even on modern super bikes. So I´d think you can have that on any bike, Bramptons, Girdraulics, high tech teles, provided you are going fast enough and the front wheel gets airborne in a second, by wheelie or jumps on bad roads. Maybe you could try endless mods to the geometry of the steering but still unable to exclude the risk for 100 percent as confirmed by modern super bikes. I would not declare to be safe with a Brampton , just that people seem to be a bit sweeter on bikes with Bramptons - no ?
Mac, your design is set a lot lower with packing pieces. What is the idea, any places on the bike that may clash with fork components - or just the hexagon bar length that holds the cylinder ? Very high packings just do not look right to me, extra bending load on levers - also found on kits sold for modern bikes - poor design I think.
Just came to the conclusion you cannot adapt the 60 mm type lever on the Girdraulics as these have more lock to lock angle of ca. 40 degrees per side ?? On the Bramptons the 60mm lever is perfect with 64mm stroke on 70mm damper, the Brampton does just 33 degrees, 66 degrees total.
Vic