Use whatever decent basecoat you want, I wont spray any other clearcoat on top besides Southern Polyurethanes now (SPI) https://www.southernpolyurethanes.com/ you will find a huge following on the net for their product for due reason, with great reviews. I just sprayed House of Kolors base with SPI on top and it came out wonderfull. I had a great hot rod painter tell me years ago why I was having somewhat of trouble getting Duponts clear (and others) to lay slick, they are not made too, they are made to duplicate factory orange peel, if they layed slick it would not match a spot repair, therefore to get a great "flat" clear you have to do a ton of cut & buffing on the clear, which after a few weeks is catalyzed so hard its a chore to sand.
My two cents here, I dont have a commercial paint booth, most dont, and SPI is formulated to not be used in a booth with air movement, making it perfect for myself, and the owner answers the phone 7 days a week, just send him a text. Good luck and have fun Matt