I've been testing using Vitamin B1... oh sounds familiar ehh! It's in Superthrive, all "Starter Fertilizers", etc...
Vitamin B1 otherwise known as thiamine, thiamin and aneurin. In the U.S. its Thiamine in the U.K. aneurin. Anyways... I've been using it on clones, newly moved clones to Flood/Ebb buckets, and in a general spray application.
I have to say I've seen a difference in how quicker and more resilient to failed cloning I've seen.
My approach is to crush a 100mg tablet into a 1 liter/quart spray bottle. For general use I use 500mg / 10 gallons as an addative for the first few weeks. A bottle is about 3 bucks for 50-100 depending on where you get it. Make sure you DON'T USE A MULTI-VITAMIN!!! Only B1.
The plants that I've done this too have grown quicker, fuller and faster than the ones that did not get B1 in the first few weeks after starting. The difference for me was about a 50% increase in size for the plants after 2 weeks. Thats the difference between a small bush and a regular growing clone.
I suggest that you also try using B1 as an addative to your cloning, and first few weeks of growth. I actually use it right through till flowering, and the difference shows. For some this may not be new, but it's the first time I've seen it here.
Give it a try on your next control grow, see how it does for you. My tomato (no-shit... for real) plants took from seed to about 4" in 6 days. With roots sticking out all over on a peat pellet. Very rapid root development!!!