I planted this specimen in November 2018. It was a gangly 5 foot tall plant at most. It has been exceptionally vigorous since then. I have had to prune it to contain it but looking at it now I have thoughts of thinning it out from wirhin to get that "airy" feel. But of course I wonder if I should leave well enough alone. (I have included pictures showing front and back).
It just comes down to personal preference of how you want your tree to look. We prune many of our Japanese maples in the summer months after the second flush of growth. I have over 20 pruning vid's on my youtube channel showcasing many varieties to view in case you are a little hesitant to make the first cut