Í have built a Skybolt a few years ago,and didn't found it to be tailheavy.
I use a OS 91 FX and set the CG with the battery on top of the main gear.
It came out at 9,5lb
So I don't see any reason to lighten it up as it flys really nice the way it is.
Then again you're doing a nice job and I'm curious what your final weight will be.

Robert