I have no experience with Imron, but I do know that some single stage paints don't color sand well. You should try in an un-noticeable area like the belly or under the H. stab. Wet sand with 1200,1500 or 2000 depending upon the buffing compound you use. My compound takes out 1500 scratches and I usually wet sand with that. Some times 1200 followed by 1500. Some compounds want 2000.
You should know that orange peel is not really related to temp. I suppose if your activator was too fast. Did you use a slow activator? But usually orange peel is related to gun settings.
You can also knock it down with 400 or 600 and put a clear coat over it. Again, test a spot to be sure you don't have mottling.
How many coats did you put down. If it is thin, you'll need to be very carefull. The uneven surfaces of these planes makes it very easy to break through. I wet sanded my epoxy and had several break through's. Even a couple on my final color sanding. I would give some thought to living with it depending on how bad it is.
I shot one coat of clear on top of my single stage and sanded half of it off to git rid of dust and light orange peel.
Larry