Im building a G.P. extra 300s. Ive chosen to go with an o.s. 91fx and will be mounting it on its side to accomidate a bison pitts. I have the engine mounted using the mount that the kit supplied. However, i can tell just by looking at it straight on that there is too much right thrust. I beleive the kit calls for 2 degrees. How do I measure this and does anyone have any thoughts on changing the angle without rebuilding the firewall. Will a shim behind the mount on one side work?, or a couple of washers?