Looks as if my initial concern about sheet to head clearance was justified. The issue of putting the traveler in front of the wheel is, as Faster pointed out, the interference with cockpit lockers. If I do this conversion, I will most definitely upgrade my vang hardware, as SEMIJim and Faster have suggested.
Alternatives: How could I go about keeping mid-boom sheeting and fitting a dodger? Or building some sort of structural support in front of the wheel for the traveler. Or moving the wheel/reverting to tiller? I am open to any and all options here. Again, thank you all for the knowledgeable responses!