I'll have it set to trigger regen first, then brake. Ideally you'd do it progressively, regen, then front then rear brake. So when I set up the hydros and finally pump them to set the pads, Ill set the front a little tighter then the rear, and it will first brake front then rear, with the option to lock both if I squeeze hard. The thing is, even in a high speed stop situation, you DEFINITELY want to use regen if you can. Ideally you would "slam" on the brakes, triggering max regen and max non-locking front brake. Then at about 20km/h you would prbly want to lock the back wheel as the regen stopping power peters out. Either way, I would just never, ever slam them on. I would always ramp it on, getting as much out of regen as possible. You maintain complete control while getting maximum decel that way.
Anyway, I have bee using that set-up on my powered bikes for literately 5 years now. It allows for one brake lever on the left with one throttle lever on the right. I cannot use the thumb throttles, over long distances holding them at WOT my hands cramp, its just unpleasant. I like the thumb triggers snowmobile style, but my favourite is the brake lever throttle for sure. Holding it down is easy as cake
In other news, bike is still noncomissioned due to the bleeding of these brakes being just the worst thing around. I am waiting to be paid, then i will prbly invest in a bleed kit or at least try and proccur an appropriate sized syringe for the forcing of oil through from the bottom up. I am having a hell of a time clearing the whole system because it is twice as long with two different piston sets in it, meaning twice as much air in the first place with twice as many places for it to get suck and half the bleed valves. It's the very first time I have played with hydro brakes, and I frocking hate it. There is literally like 10 bikes worth of frocking mineral oil on the ground. If it was DOT brake fluid I would be dead by now.