I would think about how you plan to vacation and how many points you intend to own. If you realistically will only make 1 trip per year, for a week or 2 at a time, I would buy at 1 resort (the one you most want to stay at). If you like 2-3 resorts, and plan to rotate through them on your once/year trip, consider smaller contracts at just those resorts, and plan to bank/borrow everything so you've got enough at the resort of the year to book your stay at 11 months. On the other hand, if you plan to make several short trips per year and plan to stay at different resorts for different trips, then it makes sense to own at multiple resorts as long as you have enough points at each one (using banking/borrowing if necessary) to book at the 11 month window for each one. There are certain resorts/times where it's very hard to book at 7 months!
As for # of points, the more points you have the more sense it makes to have multiple resorts - or put another way, the fewer points you own the less sense it makes to split them up.
Using myself as an example, I started with 190 points at one resort. I added at other resorts, but always in an amount I planned to use at that resort each year. I started with OKW and love that resort, but I knew during Food & Wine I would always want to be at BCV.....so I added 200 points there because that would get me a studio for 12 nights. I loved HH when I visited there, so I added points there to get me a 2-br villa for a week during the times of year I'd want to visit. I just added AKV, and added 150 so I could easily do a couple long weekends per year. Bottom line, I'm up over 1000 points so owning at 4 resorts makes sense to me. If I only had 200-300 points I probably would have stuck with just 1 resort to keep things simple. The more resorts and more contracts you have, the greater the chance member services will make an error. They have to book reservations contract by contract, and I can't tell you how many times they've made a mistake or done something differently from the way I intended (I have 15 or so contracts, so I know it's tough for them).
Good luck, whatever you decide. If you go the multiple contracts or resorts route, be sure to keep good records of all your reservation activity!