So, just a little update, last summer i let some twigs grow really long and attempted to do some air-layerings, they all dried out a few days after, i don't know if was the heat or maybe the branches were still too slim for that.
But the species is quite rare here and I really wanted (and still want) to propagate.

However, I'm very happy with the progress so far and learning the species.
This is how it's looking these days, first time witnessing it's red colours, redder everyday, such an amusement!

looking good

Well, all the leaves are gone, I would like to know what you guys think I should remove now, I mean, surely It has a long way to go, and I'll up pot it this spring, but I know that too many branches coming out from the same spots can lead to undesireable knots...

P.S.: I left that branch on the bottom for thickening, and later propagation maybe. But it's not intended for the final design.

What about remowing everything above the second heavy branch to the right and grow it as the new trunk? It would increase both mowement and taper.

Thanks for the response Tropfrog!

Since it's base is straight, I'm thinking about going on a Hokidachi like style for it, with smooth movements.
But I fear the reverse tapper if I let too much branches growing on the same spot, and realise in a few years from now that I would have to chop it back because I've let it happen, you know...

Also, can I remove that lower branch now (mid winter), before it wakes up?

This is the closest to what I want eventually, a more natural hokidachi, with a few stronger main branches, you know?
I know there's a long way ahead, just want to make sure I'm on the right way, cheers!

I have been doing hard prunes in mid winter and in late summer. So far successful both of the period. But I don't know your climate.

Just a word of caution on cutting branches off of Acer Palmatum - some experts (such as Peter Chan for example) advise against using concave or knob cutters for removing larger, mature branches as they don't always heal the same as other trees, and can die back as they heal, rather than fill in

I think it is a mistake to make big cuts now. Wait untill the tree is in growth. Right now, it is dormant, with no way to respond to the prune, which leads to die-back.