He did say in the original post that the battery was as far forward as practical. I think the plan of removing the weight and having an experienced pilot perform the maiden flight is the most practical solution. Most manufacturers will have some margin for error factored into the rearward COG.

Having said that, I went and looked at the manual for this. I'm somewhat concerned about the spec for the CG. This plane appears to have an 11" chord, which puts the 4-4.5" cg range at 36-40 percent, which seems rather far back. Normal CG ranges run in the 25-33 percent range. I'm not saying it's wrong, I just think I'd try to do some more research on where others have set the CG.

Brad