Once you have done 10k once, it really is no big deal, even in a C152. In California, where MEA's are often 11k or higher, you have to go at 11k or 12k, and everyone does it without 02. I spent about 3 hours at 12500, and as a (then) smoker didn't really notice any side effects.
Go and rent a T206T in the USA (because it is cheap) and do FL270 for a laugh (with 02) just once....