Tony, I am no expert but I have been modeling for 40+ years. I would recommend not ever mixing enamel paint with an acrylic gloss or dull cote and vice versa. NEVER use the glosses from Walmart or the hardware store - that is where I learned some hard lessons years ago. If I use Tamiya paint I use Tamiya gloss. If I use Model Master paint I use Model Master gloss or dull cote. On that note, Rust-O-Leum now owns the Model Master brand apparently and they cannot tell me much about what stays the same and what has changed, etc.
I am far too lazy to airbrush although it would help me immensely with the quality of my models. Here is an example of the 1/144 Canadian F-101B Voodoo. I used a spray paint from Home Depot that was close match. Did not even pay attention to what it was. After I glossed it I got this browning a year later. The gloss did not go on smoothly either. It actually looks OK like weathering, but it could have been a complete waste because I did not pay attention to what I already know.
I use both Laserjet and Inkjet decals that I make and print myself. You have to gloss cote the inkjet prints. I like the laser because I can use Solvaset to lay the decals down and no initial gloss is necessary. Cannot do that with the Inkjet. Hope this helps.