Big man gliders -
LS 4 is best, but hard to find. Go for an Astir, and sit in it first! Make sure you try rigging it, no two are the same! But two big guys should have no trouble at all.
American gliders are not very good, alas. I would steer clear of anything that is not thoroughly tried and tested. My personal favourite is the Pegase, but it's a bit tight for a big person.
The Astir is perfectly fine for your stage, you will have fun in it; get a sailmaker (yes there are sailmakers inland) to make a set of wing covers and keep it rigged all summer, you will have more flying if your glider is rigged and ready.
But it does make sense to split costs with a syndicate partner .......