First up was Jo Sonja Matte Varnish. After much shaking to make sure everything was properly mixed, I thinned it 1:1 (2:1 using a higher psi) with distilled water and shot it through my T-C Omni. No problems whatsoever. It dried quickly and to a lovely satin finish (yeah, not matte at all). If you have ever used Krylon Matte Finish in a can, it dries similar to that. Not super shiny and not super flat but a happy in-between light sheen. I really liked how it brought out the depth of the colors and yet it took the subsequent layers of paint without any beading.
Then I tried the Golden Polymer Varnish (Matte). Same story - shake, shake, shake, thin with distilled water and shot it through my T-C Omni. Now, this stuff is MATTE (flat). For you fans of Dullcote, that is how flat this stuff dries. Clean-up wasn't a problem, either. There wasn't significant tip build-up as I was using it and both cleaned up easily with airbrush cleaner.
Because this is the first time I have used these sealers, I have no idea yet as to their durability, especially with an eye towards performance showing. I will be curious to see if the nice, flat finish of the Golden will stay flat or will it develop shiny spots where the model is touched or rubbed.