"Divide the stone by 14, only people with the same passport I have use that measure, to get pounds"

I think you meant to type "multiply by 14 to get pounds" :-)

My club has a retractable gear Twin Astir which has the payload to take a 245 lb. pilot in both seats simultaneously. You need room - easy to judge if you can get a look at a glider and sit in it, type certificate pilot load of at least 245 lbs. and the hardest part - actual payload capacity depending upon the remaining payload of the glider at its actual current weight (given equipment and any weight increase brought about by repairs) and the center of gravity considerations.

Any glider you get seriously interested in, make absolutely sure that it has had a recent weight and balance performed performed correctly. That isn't always done. We have a single Astir where the weight and balance in the books done for the export C of A when purchased was out by about 80 pounds. We found out when the glider was re-weighed after the installation of all the control mass balance weight under an AD. Strangely, the old weight and balance said the glider was HEAVIER than it really was!