If you water the medium all the way it is never going to dry out. You will get a low ph on the bottom and yellow leaves on the plants. Space of the veg will be comprimised reducing maximum yeild for the electric you use. If you got to move a bunch of the beast your back is going to give you trouble.

Stressless transplanting is be gentle. I like to mix up the soil to be added in the other pot with some moisture. then put in the dry inner transplant and leave it for a day. the roots will extend out nicely. It is difficult to cause stress while transplanting. I used to trim the roots and still not see any problems.