Make a big batch, setting aside some to freeze for later. You can divide it up into ice trays or whatever smaller sizes would be convenient. Then thaw as needed in the fridge overnight.
I sometimes add spices and/or herbs with antimicrobial properties to the boiling water. Rosemary & lavender essential oil (added once the gel cools) along with GSE gave me good results. I have some ascorbic acid (vitamin C) on hand that I may try in my next batch.