The Zenoah G20 arrived and looks to be an excellent choice for the Akrobat except dealing with the cowl.  The Akrobat has a cowl shaped off a large spinner and would have the carb and muffler well out the sides of the cowl.  I'm not sure that is acceptable.  Another issue is a relief was cut in the bottom of the cowl for the valve cover of the YS 4 stroke and it would both look goofy having no purpose and would allow air to escape the cowl without ventilating the motor so would have to be closed up meaning more work on a plane I thought was finished.  It would also mean some amount of work removing the beam mounts and mounting the G20 to a firewall given three degrees right thrust.  At this point I'm not sure what I'll do... maybe go with a Saito 1.25 as it would be a lot easier installation on what is all ready there and save the G20 for the Stearman.

Update:
The Zenoah G-20 ei

Break in went very smooth.  The motor kicked on the third hand flip at which the choke was turned off and it came to life the next flip.  Idle was smooth and low.  After about a half hour running time, it was run up and reached 8,200 with a 16-8 APC prop.  This motor seems to be about equivelant to a 1.2 4c.  It will however be much cheaper to operate as it is uses much less fuel than a glow motor and the fuel is considerably cheaper.  The G-20ei is a sweet motor with the only drawback a high current drain on the electronic ignition.  An EU outfit however suggested less drain and good operation could be had from a three cell battery pack rather than a four, which is the route I've gone, using three cells from a surplus tool battery pack.  As my quick charger has an adjustable knob for charge current, it is easy to adjust charging for the three cell pack.