If you really want to get tricky you can use a 273 crank but it takes a bit to get it balanced.
I used lots of them, but I was running aluminum rods and had a bobweight that was under 2000 grams.
I've also turned the counterweights down (need a damn rigid lathe or a crank grinder) to almost the rod throws. Takes some Mallory to get that balanced.
You can do some serious mental mastubation on this stuff and end up spending a bunch of money on things you can't really prove effective.
