Hello and welcome to the forum.
I read the information on soils at the top of the forum and couldn't get much help.
What specifically are you having trouble with?
What soil mixture would be best for a bonsai growing in VA.
Ynot used to grow Ficus in N. Carolina before his transplant. I know he was/is fond of an entirely inorganic mix. I have been keeping mine in a similar mix as most of my other trees, about 20% Pine bark and the balance inorganic. Recently my main inorganic components have been Haydite, which is fired shale and Lava rock.
I think you will find that the subject of soil does not necessarily need to be overly complicated. For now be aware of the proper components and texture. Exact ratios can come later after you have some "yardstick" by which to measure your results.
Also, my ficus looks like it's ready for a new pot soon. (even though I just got it.) How do I know?
Try to judge how root-bound it is. Can you remove it from the pot without the rootball disintegrating? This will determine if it can go another year.
Have you seen Jerry's site? There is much information on Ficus there.