I have found that I can achieve a gloss coat, on horizontal surfaces but not on vertical ones. I have tried airbrushing Future and lacquer gloss, as well as rattle can lacquer. However, my vertical surfaces have an orange peel effect. Do I have to keep rotating the build, so the vertical surfaces become horizontal ones? Or, is there something I am missing? TIA

Orange peel can be caused by a number of things.
1) Paint too thick.
2) Too far away.
3) Pressure too low.
4) Not applying enough paint.
5) Any combination of the above.
Paint a flat piece of plastic with your commonly used paint, support it vertically, and make changes/adjustments noted above until it paints OK. DON'T play with the changes on your model. You will make a mess of your model and not be happy.

If you're getting an "orange peel" finish (looks like teeny waves on water) with gloss as you describe, you're putting on too much paint, which is very easy to do with clear coats. On the horizontal surfaces, the paint is getting a chance to self level before it dries, giving you a smooth finish. On the vertical surfaces, you are dangerously close to getting sags and runs.
Especially with clear coats, gloss or flat, it is important to cover the model in wet, thin coats and build up the finish in 6 -8 coats, with time in between to let the coat set up.

Sounds like I need to apply more paint on the vertical surfaces. My pressure is high- ~30psi
I'm spray ~1in from the model
Paint density is between 1:1 and 1:2, when I thin it. Normally, I don't.