I painted my main gear wheel wells with the same paint as I painted the rest of the aircraft - white Durathane. It wasn't hard to apply; I just held a small touch-up gun in there and 'sprayed and prayed'. I am so glad I did that, because the white paint makes it easier to see in there, and the Durathane resists the inevitable hydraulic fluid. I did primer the wheel well first with the epoxy primer, but just gave it a light sanding. I wasn't going for beauty, just sealing.

In the nose gear tunnel, I tried "Oceans" entumescent paint. It didn't work at all because it flaked off after a year or so. I can't help you there, mate.