Poly is easy to get both at the 11 month mark and the 7 month mark, and May is not a high demand time. You will not have trouble.
Edit: I agree with earlier posters that you might have trouble finding someone with poly points to rent. However, if you are going in May, at a time other than Memorial Day weekend, I really think you’ll be able to rent at the 7 month mark without a problem (and at a lower rate) using anyone’s generic points. May other than Memorial Day weekend is historically a very low season. If it’s Memorial Day Weekend you are travelling, you still might have a shot at the 7 month mark, I’d say it’s 50/50.