thanks for the replies!
this is actually one of those situations where you can't use oil-blotting sheets. my cousin is getting married next month overseas in a restaurant with 300+ people, no AC, at least 90 degrees, and she can't do anything but stand there. there's no going to take a break, blotting, reapplying makeup, bathroom, etc. i told her tinted moisturizer would be a better choice since it'll be so hot, with powder over it, but she had no idea, so we were both stuck and couldn't figure it out.
thanks!