Welcome to Flyertalk.

Not sure about this topic, but would be worth knowing if awards could be used concurrently; if you are at least an HHonors gold then you get upgrades without any extra coupons.

I doubt if you can use more than one coupon at a time but unsure? Given that no one responded sooner you'll probably need to call the HHonors desk and ask.

Report back if you do.