Taper?!? Does that mean fat at the bottom and "tapering" up?
Ya my tree doesn't have that lol...how many years would it take to develop taper...
Yeah that... you have to work it. If you let it grow wild and then chop off where reverse taper happens, you'll grow a new leader getting rid of tapper. Another way is to grow sacrifice branches close to the base, so the trunk below it thickens up. I am not experienced with Ficus, so maybe an expert could help you more. But I would suggest 2 possible approaches.
1) Prepare the tree for air layering: Let the tree grow wild for a few years, once the tree is healthy and has a thick trunk, select a new trunk base for your tree and use the air layering method to get rid of what's below it.
2) Cut n grow: Put the tree in a big container and let it grow wild until desired trunk thickness is achieved. Then chop it and grow a new leader, let grow again for a few years until new leader reaches desired thickness. Chop new leader, now grow the branches.