Hey delphene,
I too get very sweaty, but what i found best was finding material that is a little more durable. You can try Lorna Jane (for their crops, running singlets and tanks, leggings and shorts), or lululemon atheltica (love their leggings). If you want exceptional quality, then you can try Brazilian active wear. Although its expensive, it is actually worth it. The brand that i like is Brasilfit and their material never changes shape and colour no matter how many times you wash it. Some other brands you can try are of Brazilian active wear: Braus, Fashion Brazil, Brasilsul. Plus the fit is amazing and firm and i dont feel as hot as if i were to wear normal tights.....
Hope this helps! :)
RPM + Attack + Pump + Balance...I breathe on les mills baby!!!!!