Never paint hammered...
Should be fine, especially for what you want it for.
You might try to paint around the bead area with gloss though.
Since its winter time, you might stick them in your oven one at a time to fully cure the paint. If you do this, do NOT overdo it. Lowest heat (say 150) for a half hour will do wonders for durability. If you can't set your oven that low, heat it up, turn it off, when it's at 150 toss the wheel in there, and leave it for a half hour. Repeat for each wheel.
Oh - and it will stink up the house and get you in trouble unless you're a bachelor - be warned!
An alternative is a heat lamp, out in the garage....
Heat from brakes should not be an issue, the wheels themselves don't take on much heat. Your hood gets hotter from sitting in the sun on a summer day than your wheels get after a good hard braking. Plus, it's usually cold out when you run blizzaks.