My bottle of GAC 100 doesn't mention drying time. I usually give it a day. Someone mentioned they make a new product that is supposed to be better but I forget which it is.
Golden Acrylics recommends allowing at least three days for acrylic products to fully dry before painting on them with oils. Of course, you don't have to wait that long before painting on them with other acrylics, just wait until they are completely dry to the touch.
According to Golden, Golden Gloss Medium (formerly known as Golden Polymer Medium Gloss) is actually a little better than GAC 100 at sealing, but both are fine. They recommend 2 to 3 coats.
This info was in a Just Paint article about Golden Open Acrylics, SID, and shellac because apparently Golden Open Acrylics dissolve shellac-based primers and sealers commonly used on hardboard panels, resulting in SID (support induced discoloration) of the paint from the wood. Regular acrylics do not have this problem with shellac primers.