I don't own there, but I do own at multiple resorts. The questions I'd ask yourself is:
1. Do you plan on doing a split stay each time? If so, for how long at each resort and in what room category? What time of year? Purchase a number of points - plus a small cushion to protect in case of point reallocations - each to the amount needed each year at the resort
2. Do you plan on switching between resorts (one year VGF, one year BLT)? If so, again, what category, what length, and what time of year? Use the
point charts to determine # of points needed, though in this case buy half the amount. You can bank or borrow. For example, first year is VGF, you use current UY points + borrow for your stay. Bank your BLT points. Next year, stay at BLT on the banked and current UY points. Repeat.
We ended up buying points to allow us to do at least a week in our resorts, with the exception of HHI and VGC which are for long weekends. We figure we can bank to upgrade accommodations if we don't go to a given resort (so going from Studio to 1BR, or 1BR to 2BR), and worst case rent out points to cover dues if we decide not to use them at all.