The guy who balanced it for me did a good job balancing but not such a good job making it look pretty.
The skirt clearance cuts will clear 5.7 inch rods. I am using 6 inch rods this build. I used a big lever to swing the crank on crankpins under the milling cutter to make the cuts.
No Mallory required. Balance the crank all by itself or with damper and/or flywheel but no bobweights like you need for a v8.