More mass = more heat and shorter work time.
I like use both a gel coat dump gun, or a Imported HVLP, to my Binks #7 & #19 guns and one is a pressure pot 2 qt. type.
For PVA: Harbor Freight 9.99 touch up gun, but after cleaning with water, don’t leave any moisture in there, blow it out and pour a little paint thinner to oil it up safely but also spray a little out too.
While in Paramount, Ca. (there several direct importers shops there) is like Inpac Tools (next door to a great aerospace supplus discount store too),13902 Paramount Blvd., Paramount, Calf. 90723
They have these great little HVLP down draft touch up guns (andodized blue) that will do a great job on PVA & Clear PER Duratec resin costing too. Under $20.00 no less. I ususally buy 2 or 3 just in case we are working or sometime and can’t take the time to clean a gun, we throw in a simi dirty acetone bucket first, finish the problem and then clean the gun in the clean acetone bucket. Then put itback together and spray paint thinner thru it to oil it.