When I was pampering my blueberries, I'd mix a 'fancy' fertilizer solution in 32 gallon garbage cans. I'd adjust the pH with acid, add MG and Ammonium sulfate, sometimes epsom salts, and water the bbs with a bucket.
Hadn't thought of doing that with figs - having a large container of ready-mixed, but dilute fertilizer solution ready, but it's something to think about since they all are in pots. That made it very easy.