Martin... Thanks for the offer and let me look into those! Would cost another ten dollars to get them to Thailand but I might still be ahead.

I've been reading a lot of threads and it seems it really depends a lot on the engine. My Tartan is incredibly smooth at higher RPM, but at idle it shakes my 1/2 inch plywood box so much I can't imagine what it would do to an airframe. I'm not that good of a builder!

Have to admit that I haven't tried leaning the idle mixture which a friend suggested. Apparently that helps tame the lower end vibrations a lot. Wondering if you have experience with that?