Repot young Japanese Maples
I just purchased 6 Japanese maples and was hoping someone could give me some advice on how to handle them. They are all young and look healthy, around 20-36" inches in size, and are fully leafed out. They came in #1 pots in a mix of Sphagnum peat, perlite, and gel cubes to hold moisture. There is also some composted material in the mix and some topsoil. I mixed up a batch of 1-1-1 gritty mix earlier this week. From what I've read here on the forums, I believe it is too late to do a full repot with root pruning.
What is my best course of action to handle these young trees? Is it too late to carefully wash away or separate the existing medium from the roots, untangle them, and pot them up in my gritty mix?
If it is too late, would I be better off moving the existing root balls into larger pots and surrounding with gritty mix?
I appreciate the input. I don't want to make a fatal mistake and kill these trees the day after I received them.