Alan,

I mounted my YS 1.10 inverted too. The engine mount beams are almost even with the end of the engine mounts.
I am using an APC 16X6 prop and found that it tends to pull to the left on a straight vertical upline.
So, I brought it home and put a washer between the firewall and engine mount in order to give it some right thrust to help correct this.
But I have not flown it since I mad this adjustment.

Barry Finck