With paint, you'll need to consider an air-powered or a force-feed unit like the pros use for large jobs. I know the force feed units (Graco) can handle paint without any additives. Air powered need the force to get the paint to atomize. Lots of fiddling but with the right equipment and needle/cap selection it can be done. For air power, there is siphon fed and pressure pot fed. I believe that a pressure pot would be the way to go for that if your compressor lacks the required CFM.
Post job cleanup ease is another consideration.

I don't paint many things so I have not yet found a good comfort zone with my HVLP (Earlex 7000 series). It certainly didn't test well with the stock 1mm nozzle set. I have a 1.5 and 2mm but haven't tried them.

In my opinion, thick "brush" paints are the most difficult thing to spray with good results and it comes down to the right equipment which can be $$$

Maybe check out the rental places and see what equipment they recommend for those jobs, at least you can be introduced to equipment that has been proven (otherwise they probably wouldn't rent it)