Gloria sprayers are good uns. Just make sure (as you probably know) that all the seals are VITON and not standard rubber ones as the xylene in resin eats rubber quickly. The non slip additive soon sinks to the bottom of both tub and in the gloria so you have to constantly keep agitating the resin (co the additive don't melt into the xylne)
Also the additive particals have been known to cause blockages in the gloria nozzle oriface and the filter.
If you put to much additive in and it clumps in one area you can see it when resin is dry, it looks like salt on the surface and it's VERY DIFFICULT to remove as you have to take resin off.
There is a new additive just coming out that is ok in the resin, the resin is supplied with it mixed in as a LOW slip resin for pic.