If I get the chance this weekend, I'll bench run the Syssa on my mount. I'd like to run it to get the needles set and make the initial set up in the Focus a bit easier.
FlyEng, I think you will be very happy with the way your mount works. Your craftsmanship looks superb, and I am particularly interested to hear about the movement (or lack thereof!) in the spinner area. I think there will be very little if any, and I'm hoping that we won't need nose rings at all with these mounts.
Just remember, if you plan to run it with the pipe the needles need to be richened up a bit because fuel consumption goes up with the pipe. The factory settings are for the Pitts muffler, which are lean for the pipe. I had a bit of trouble with the first couple of starts until I richened it up. I don't remember how much (because I was kind of flailing around and didn't write anything down) but I'd guess about 1/3 turn for High and 1/4 turn Low and then work from there.