geoHarry,
I am going to have to disagree with you. I was turning an APC 16x4W at 10,300 on my Saito 100.

I was getting the same RPM's with a Zinger 16x5, with quicker spool up than the APC(the Spool up is negligible w the APC, but noticably less with the Zinger).

But of course you do pay for the extra power and 4-stroke sound.

Gotta love the putta-putta.