Rustoleum isn't that great.
Try POR-15 alone if you store your frame out of the sun. Top it with HardNose paint if you store your frame out in the sun. POR doesn't have UV inhibitors and will get chalky with continuous exposure. Stored inside, used outside should last years with no topcoat. POR is similar in durability to powdercoating.
I see you're in Missoula will have open cans of POR ($45/qt) here in a month or two. HardNose paint will be yellow.
If you like yellow and want powdercoating, Rick up here at Replay Sports frequently has Advanced PowderCoating doing complete frames (as loose parts). I'm sure you could get your LoPros done with one of his orders for less than you'd pay to get yours done alone.