Looks like an interesting setup, I imagine a call or email to the builder might get you some info on that. Let us know what you find if you do.
I have the second design Hegar unit on my CRG now. They revised the design over the spring/summer and now have a better scheme for engaging the flywheel than the original. It has worked very well for me. With regard to seat clearance, I moved my seat over about 3/4″ to make more clearance during this second install and reweighed. The effect of seat movement is somewhat offset by the offset engine mounting required. As it turns out I could have afforded to move the seat even more left because at this point I am still slightly heavier on the motor side (49L/51R %). Since I’m over class weight already I’ve chosen to let it ride, but I could easily true it up with a little more weight. As far as handling goes, its imperceptible to me, but ymmv.