Not much you can do without mangling the roots. I spent along time going over this in my head pretty recently wanting to pheno hunt in a few totes. Decided against it because what I was planning to run were regs and the options were cut the males down at the trunk and leave dead plants in my reservoir or mangle the root balls trying to get them separated.
I chose fems instead lol. I had shit all planned out too till someone brought up the issue of culling males.