I would forget about ramification at this stage and focus the trees energy to enhance the quality / visual age ( thickeness) of the main brances.
Grow and Cut them back in a few years time - well some of the existing ones will be shortened quite drastically to remove the straight sections to start with. But it is better for the tree to do it right at the beginning than later.
Repeat the same to get conicity.
Start with the ramification once the main branches are ready. The main task here would be to SLOW the tree as much as possible to get shorter internodes. Based on ones aspirations this requires a lot ot time as you should remove any branchlet that doesn't have required quality.
There are some other things than just a horticultural quality of the tree - a design for one but that is for a longer conversation. ig position of low branches on this tree evokes the feeling of a young tree rather than an old one...
The autumn colour of Amur maple is simply great. This one is no exception. And yes, it looks healthy. This means quite a lot to me... The rest is just my way.