I've had mixed results, some 4" blocks are holding up great and I'm seeing good growth in the plants. Others not so much, they seem to be unable to send roots from the 2" into the 4" block. While they generally end up managing it, there growth slowed down and some of them got stunted. I think I waited too long to transplant them and those blocks that fared the worse had improper aeration underneath them, meaning they had sent out roots outside the blocks.
Once I'm done with some specific gardening tasks, I'll do a test run comparing the soil blocks to these new trays I just got; the neversink farm winstrip trays: https://www.neversinktools.com/collections/winstrip-trays
as it seems like I could get the best of both worlds this way.