Lesser evil

I would go with 6/4, keeping the best priming structure, duplicating 5 for white, also minimizing hitting chances.

Not sure about the "duplicating 5 for white".

I'll go 8/6 because it puts a spare in a good place and doesn't create another inside blot for those times we get hit on the 22. I can see 6/4, keeping the best prime, being correct, also.

Maybe 6/4 is right, but the standard thing to me seems like 8/6 which keeps a better board, better spares, and still blocks the big numbers pretty well, including 6s which play badly on Black's side of the board. It lets Black out with 3s, but 33 is kind of OK on the other side of the board if the 3s are blocked, so there's a little bit of duplication.