Glad you're taking a little more time before buying! If you love the Poly and usually stay there it may well be the best choice for your family, and when buying Poly it often makes sense to go the direct route through Disney. Still, it makes sense to understand everything thoroughly before making a big purchase.
I would suggest getting at least a few more than 74 points due to possible point reallocation as described above. At least 80-85, so you won't lose a whole night of your trip if they make a slight change to the seasons. They won't let you add on less than 25 later, so adding 5-10 now might be smart. How old are your kids now? Will their schools accommodate a Sept or Jan trip every year as they get older? If there's any chance you might have to travel in a costlier season, you might want to use that point cost as your target.
Enjoy your research, I thought it was fun!
I would suggest getting at least a few more than 74 points due to possible point reallocation as described above. At least 80-85, so you won't lose a whole night of your trip if they make a slight change to the seasons. They won't let you add on less than 25 later, so adding 5-10 now might be smart. How old are your kids now? Will their schools accommodate a Sept or Jan trip every year as they get older? If there's any chance you might have to travel in a costlier season, you might want to use that point cost as your target.
Enjoy your research, I thought it was fun!