Keep those low branches and try and get the base even fatter. I am not sure why you recently pruned - I think it was too soon. A tree like this can grow 1 or 2 meters easily in a season - that is what puts on the thickness at the base of the tree. When you prune - you slow down the growth "engine".
It is a very straight looking larch - you have to try and induce some movement in the tree at some point [unless you want a very formal straight looking tree...] - you can do this by cutting the trunk back hard at some point and then taking a side branch and growing that is the new top. From the photos - I think it is too soon for the chop...
I would not be afraid of keeping the sacrifice branches that you have - the pruning scars can heal well on a larch and this can help thicken and roughen up the base of the tree - give it some character...