In RL, Gehrig generally batted behind Ruth so opposing teams would actually pitch to Ruth. That's not as big a factor here, but IBBs are still possible, so if you want Ruth to crack those homers, and nobody else in your lineup could protect him, I'd go Babe 3, Lou 4. I'd also want two guys with good potential to be on base batting ahead of Ruth, not just one, to increase the chances his homers would be two- or three-run shots, and to give them both more RBI opportunities.