The interrupted cut is no big deal. I wrote all of this up 20 years ago. Fairly simple to drop the crank in a lathe and turn down the counterweights and then put a chamfer on them. With a little bit of math you can figure out how far to turn down the counterweights to get the bobweight right on. We used to turn down the 440 cranks and then only have to drill a tiny bit to get the assembly to balance. I haven't turned a crank in years though since the stroker cranks have gotten so cheap. I do still have a stash of steel 440 cranks on the shelf but not sure I'll ever use them. I did finally throw away all of the stock rods I had been hoarding.