WillsC,
I believe the vascular flow will be a problem as the main trunk gets larger (older), if you change directions abruptly. One of the reasons for balancing the trunks is to allow for uninterrupted flow to the verticals, all the energy of the tree is intentionally directed to the fruiting verticals. Leggy is good : )
If you can get as much vertical growth as possible before placing horizontal, you will save yourself a lot of work.
I have 4 branches that were to be laid horizontal, they were placed on a 45 degree angle, they have now branched and have stopped growing on the vertical, and I'm 3 feet short. I now have to prune off all the branches and place it back in the vertical to gain the required height, before placing horizontal again.