TD,

I did not use the spacers between the firewall and the engine mount. I could not figure exactly now these were supposed to go and, quite frankly, I can't see where they are needed. Anynow, the cowl lines up very well and the plane flys extremely well using the pre-drilled holes and supplied mount. It can't be much easier than that. I have the YS 1.20 mounted inverted--it works well and the combo does not have excessive vibration. Just a good, solid airplane.

Sam