There is one single answer that can be used across the board as far as creating taper is concerned.
It is an equation with a lot of Variables, the variables being where you cut the first time, how gradual the taper, how tall the finished tree, etc., But it is possible.
Possible because it is only going to look right to a certain degree, certain parameters you must stay within.
This can be calculated.
Problems arise when the tree doesn't cooperate.
That said...
I have a problem with the fact that this question exists at all.
How far up the trunk would you to prune back this maple in order to establish good taper in the future? Which branch should be the new leader?
Since taper is gradual by definition, this question is not whole. Answering this question doesn't create taper, it creates an abrupt change in size.
However...
You can enter your tree into the taper calculator based on any first cut, and understand how large and long your next segment must be before cutting it again to a certain node.
Sorce