You are on the right track doing the research. Ficus in its native climate is not picky about its soil mix and I don't think it needs akadama as it breaks down after a while. Ficus Macrocarpa like to have its soil on the dry side before watering again. I use about 70% commercially available free draining bonsai mix added with 30% potting mix for moisture retaining for my ficus. To me using 100% bonsai mix requires too high of watering frequency for my actively growing trees.
If you just got the tree I'd recommend waiting a couple weeks before re-potting. Some ficus go through a transition period that makes it shed some leaves. Best time to do it is Spring but it can be done year round on a healthy, growing ficus.
ficus, maple, elm, juniper, pine