The 10'1" spread would be better overall but the way I read your post was that you were upset that your drives were so much lighter than the trailer tandems. Sorry for the confusion.

That's why I think it's great to have the front axle slide from 121" to 72" position, while the rear axle is fixed as far back as the kingpin rule allows. I'd use the long spread only when it's required and stick to the 72" spread most of the time for better fuel efficiency and longer tire life.