Last year I started to make some clump tridents for later. I tried one as an experiment just to see how long they take to fuse. Not long! It has not even been a year yet and they have all fused at the trunk, grown roots on top of the tile and the nebari is looking very nice so far.
I drilled a hole in the bottom of a terra cotta pot saucer to use as a tile. I used this because it is soft to drill thru and I can drill any size hole.
The cuttings I used were from the previous years crop. They were about like a match stick and about 4 inches tall.
This is the base now 11 months later. The trees are nearly 4 feet tall and the base has fused into a cool tapering mass and the nebari is spread out on the plate. This spring I will remove it and trim the large roots and place it into a larger colander and then grow it for three years. Meanwhile, this year I will start a new larger piece like Gary Wood does it with a larger plate, larger stock and drill them a couple inches a part in the shape of a number five dice. This will give me a single tree with massive melting nebari and a single trunk.