Ok I use E'tac's PS line as well, along with the efx, and golden high flows. Here is a copy of the text I posted about varnishing recently in reddit that might be useful here:
If you used acrylics create a barrier layer first. I'm a fine art painter, and varnishing is a crucial step. You can use any acrylic base or medium for this task. I personally finish using Golden Paint products so first I make up a sprayable acrylic medium by diluting Golden Soft Gel Gloss Medium 1:1 with water. Making light coats I'll spray 2-3 layers. Let dry for at least 24 hours cause the next step requires mineral spirits. Then using Golden MSA Varnish & Golden MSA Solvent I again dilute the varnish into a sprayable consistency. On a flat surface, in hopefully a dust free area, spray 2 light coats. Again let dry for 24 hours. For smaller pieces I use my .5mm iwata HP-TH, and for larger paintings I use my iwata W101 with a 1.0mm nozzle. Use the MSA Solvent to spray thru when finished, but don't end there, afterwards breakdown and clean your brushes per usual. I have finished work with a brush as well, but since this is a delicate process I have a $90 sable 3" flat that is designed just for finishing.
If you get runs don't panic, that's what the barrier layer is for, you can use MSA Solvent to reactivate and remove the varnish. That's why this process is so critical in the fine art world where you might have a conservator come and remove yellowing varnish or repair any paint. If they have to repair or refinish the barrier layer makes it so they can repair a painting without having to touch the "actual" painting that the artist did. A word of caution though don't use 'odorless' mineral spirits, they put in wax and remove the harsher solvents that make it soluble with the varnish. You can tell if you're using a weak solvent if the varnish turns cloudy, or has waxy chunks in it. To shortcut some of this you can buy MSA varnish pre reduced in a spray can, but I personally like having more control over the process, and having pure solvent on hand just in case a problem occurs, like runs, or a piece of lint drying on the surface, in which case I can dab a qtip in solvent reactivate that little spot, remove the lint, and have the varnish re level.