Ken, bone on, bone off, it depends on how much work you can handle and how easy you want to make it for your guests. You first need to decide on portion size, and then how you are presenting them.
If your last experience with duck breast was satisfactory, don't change anything providing they were wild versus farm raised. Wild game is a 2x + when it comes to cooking time when compared to farm raised.
If platter, as in family service, I'd leave the half breasts in one piece. For plate service, it's a nice touch to slice across the pheasant breasts at an angle, or bias, and drape the slices over a base of something like wild rice with pecans and dried blueberries. Never flat on the plate because it says you don't care to your guests.
Twelve half pheasant breasts aren't very big. Package them in fours if you can. And if you are able, SV cook them the 3 packages all at once. It will add 5 years to your life expectancy. If you don't have a large enough vessel and can't borrow one, you might want to reconsider producing this meal.
You don't need any fat to SV cook pheasant breasts. Season them well before giving them a quick sear. Be sure to carefully check every piece for shot.