Kids are very funny and if you share too much info with them it gets even funnier.
Make a few adjustments, just to test, but don’t tell him anything, just let him drive it, and see how he does. I was checking out the videos from this Saturday night race, and he looked really good, nice and smooth, and very consistent.
If you really wanna try 52″ at the rear, he may lose lift at the inside rear tire, at the pit turn, but considering how light he is it may work to his advantage. Try it first, and if you don’t like it you can always go back all the way or closer to 49″