"I want it to be as balanced as a high revving race engine..."

Get it balanced. OEM balance tolerances are, at best, sketchy. It's apart. Do it right and take it to a reputable machine shop to be balanced.
Also, here's a formula:
Rotating:
2x big end rod
2x rod bearings
oil (approx 5 grams)

Reciprocating:
2x small end
2x wristpin
2x piston
4x (or 8x if dual spirolox) wrist pin retainers
2x set of rings (include support rail if applicable)
multiply sum of reciprocating by 50% (51 or 52% work if you are consistently over 7k rpm)
add that number to the rotating sum and you have your bobweight.

Now get it balanced.