@robertobaz2, aunts and uncles won’t provide a legacy boost, only parents (sometimes grandparents) - in case of aunts and uncles they would need to be very large donors (think building named after them) to make a difference.
As an atm approach, your current selection process seems fine. Personally, though, I regard matches as an essential school category. As you stated earlier in the thread, broadening your base of potential match schools would seem to be a good idea as well, @robertobaz2.
agreement (#37): Differentiated -> Differentiating.