I'm sure your electric mustang is without a doubt faster than any gas competitor of equal size as is the reliable power and ease of daily flying. I've never really got into elec's on anything larger than 60+" 3d planes however I do see the advantages.
Regarding your ZDZ...You could actually increase the base gasket thickness by a few thous to slightly help reduce the compression ratio. I have done the exact opposite by decreasing the base gasket thickness to increase compression = slight hp gains. I've done this primarily due to the altitude we fly at in Colorado. +6,000 ft at the field = everything bad for rc planes. Thin air = less lift and less prop thrust performance. Low oxygen= less fuel for proper mixture making lower hp. I have a CNC cutter and have cut several thinner copper gaskets for different engines with fair results.