I'll second the recommendation to have it powder coated. My local powder coater charges around $150 for a single color with clear on a frame. That includes stripping any finish that is already on the frame.
Painting a bike frame is not easy with a spray gun. There are a lot of tube intersections that will easily get overloaded with paint and run. There are also spots like the underside of the seat tube/seat stay junction that are hard to get paint into, especially with a large automotive sized spray gun. I have painted a number of frames with this detail spray gun from Harbor Freight tools.
https://www.harborfreight.com/adjust...tail+spray+gun It works fine for a $14 spray gun. I use base/clear paints from TCP Global. Spraying the base is pretty easy and there is not much chance of runs with that. The clear is where you have to be really careful not to get runs.