I am a very active member of the PTA -
if I had it my way you all would get a DVC Contract as a perk! In fact, that is a GREAT idea to give to a friend of mine running for School Board!. Not that we should pay for everyone - but - it is a rather inexpensive perk to be awarded to you fantastic folks that educate our kids!
My personal Observations:
1) Here in our school district we have gone to "Year Round Schools". Our kids start Aug 1, then, get a week off in September and February. The first year that this took affect we went to WDW the first time in Sep we found low crowd volumes and ran in to a ton of neighbors where we agreed: "How great is this?". Now we have one in HS and one in College - so it makes it more difficult.
2) WDW in July / August is not the best time to go - this is my opinion - Big crowds and blistering Temps is not any fun!
If Summer / Aug / December or Spring Break is your best option, then, understand it is a popular time to go and you will be in competition with others for a reservation.
3) Will 150 or 160 pts work? Tough call - if you have a week off in Sep, then it probably will. If you plan to buy 150 and go to BLT and get a Grand Villa in April - good luck. If your only desire is to buy in to BLT and get a Studio once a year - maybe you are ok. Not sure anyone can answer unless you give more specifics on how you plan to use it.
The best advice I think I can give you is this: Buy in to the resort you love so you have the advantage of the 11 month ressie window. This is the MOST important advice I can give you!
My opinions - hope it helps!