I went to the Test Server to test out a build shape I had in mind. I came up with this. The triangle sides can be any length with those ring sizes. It’s an equilateral or “regular” triangle tho so the sides need to be all the same length. In my way, the ring is formed first (3 Wedge, 2 block, repeated) with the long side of the 1st 3-wedge group facing whatever direction you want the 1st side of the triangle to go in.
The rings can be split either initially or afterward by splitting either of the two square block pairs (across from each other) which do not form a vertex of the triangle. So if you wanted an capsula rather than a circle just add blocks there.
To fill in (or extend) the rings just add the opposite block type: Where there is a square block, add wedge blocks and where there are wedge blocks add square blocks. I dunno if there are various ways to fill the insides of the triangle - there probably are - I just went this route cuz it was easiest.
My idea was to encircle a few of the redwood trees - as I live in the giant forests on the isle of Siptah. 
I used these white block set so I could see the patterns better. So that’s me in blue, flying about 50 or 60 meters above the shape.
On the second floor each ring is large enough to hold all of the T-1 crafting benches in the game - one of each as well as the tree trunk but you may want to extend the shape of the rings as described, for a bit more room. And of course the shape can be patterned in any of several ways to grow the base or make a larger initial structure. -=shrug=-
It took about 120min. to construct the final building and get it so that the trees I selected were centered in the rings (or the differences split).
Night:
Day:
Various other angles:
