Theres not the room in the linkage for the HM strain guage. There is some sort of arrangement that can be bolted behind the frame just above the gear lever. Ive got a HM on my z1000 which is brilliant but, id have to say the Healtech is better value for money plus is fits into the existing linkage of the hyper (my 1100 is near as dammit the same as the 821/939 with regards to fitment and sizing). The healtech has more control and more features and, is easier to configure/use than the hm given the HM it almost twice the price. I think the base HM is close to 400 whereas the Healtech weighs in at 240 quid. If there was room in there for the HM then it would be closer but seeing as youre going to have to fuck about to get the shifter in there that costs more its a no brainer...i did have some problems setting up my Healtech but, first and foremost Healtech support were brilliant, the initial seller was also really good and the importer also weighed in and, when i needed them sent additional stuff also for me to test. I have posted all this in another thread but the problem was the engine cut test didnt work but, the QS actually did work correctly all along, for some inexplicable reason the cut test didnt. Ive not tried it since as its working brilliantly. Not sure what the 821/939 is like but 55ms is a good starting point whatever you fit.
Not sure how the pegs are on a hyper or the length of rod, but if you go race shift it could then take a direct lever fit maybe? Or look at the one fitted to the multi, as the rod length can't be smaller than that. You could give @Desmo Dave a call at WM Snells, he knows about these things and when I was in there last was working out linkages and rods for an x-diavel
The Rod is about 30mm long or thereabouts....the healtech sensor is a small hoop that fits over the top of the rod (about 5mm) - thats it...as i say it saves on the hassle of finding alternative place to anchor to.