Not knowing your real size, it's hard to say about the Pampers.
But, you can order adult diapers on line. Allot of them sell samples, 1, 2, or 3 at a time. And most ship in discreet packaging. Mostly they will be in a plan brown box, with just a company name, and even that is usually discreet also.
Here is a place to start with, they sell samples. It works out to cost more, but if you want a few at a time this is a way to do so.
I don't know if they would send you one, but you also might write to Pampers, and ask if they would send a sample size 7 cruisers diaper to you. If you offer to pay the postage it might help too. That way you could try them out for size.