There's no way I can test-play classes at 90?

I was hoping for a lvl 90 boost server, so i can test play out a few classes that I remember being my favorites in mop. after that, i was gonna set myself to levelling one for real on Warmane. but I want to pick a class after looking at the abilities and feeling them out and all that, you know? I'm torn between a few of my favorite classes at the time, and I just want to test them out. Any ideas? can i change the files so that I'm using a PTR version lol?

thanks in advance

the only way to get an instant 90 is to buy a character of someone else, which should be 30coins for a lvl 90. However, leveling is x7, so it really is quite fast to get there