All three were roughly the same size and had similar root deveolpment when I potted them three weeks ago. Same position and care, although the keeper has had a bit more water due to the open mix.
Pretty dramatic difference in growth. Sample size is too small to make a scientific judgement, but I thank Ausbonsai muchly for the wonderful advice given in this forum

I am new to bonsai (and horticulture in general) and, following the advice here, have been mixing my own substrate. With no prior knowledge to compare, I didn't know if my labour was worth it, but now I am convinced!