If it'll help, here's a spec. sheet from an A65 crank balancing I had done in 2011. The pistons were "Rocky" mfr. & the rods were standard '69 BSA A65 rods, 70% balance factor. He added (one) Heavy Metal insert (7/8" x 0.5") & I recall what appeared to be several 'lightening' drillings.
(sorry , since the demise of PhotoBucket I struggle with photos/scans.....hope it shows up.)
[Linked Image]

Attached Files scan0029.jpg