“...what is the shortest time from re-potting to putting into the ground that would make the potting substantially useful?”
In my experience, four weeks from 4-pack to in the ground.
That’s what I figured, I’m just going to skip the repotting, I almost skipped planting anything and don’t really care about maximizing yield or getting my 9 foot tomato plants this year, I just want a sparse yield anyway, last year I kept myself busy messing with plants and hauling the yield to neighbors, it wasn’t worth the water.
Way too many variables so there is no specific time that can be given.
Best bet would be to pop one out of the pot and see if there’s any signs of being root bound. If not, feed them and plant in a couple/few weeks when they will probably look better. If root bound, pot them up and wait for them to “grow larger and healthier, and stronger” and then plant them out.
Even recovery time for repotting is variable. If zero root bound and zero root disturbance in the repot, they won’t even know they were repotted, hence zero recovery time. If the roots went around in 5 circles and you have to do some ripping, yeah, they’re gonna need a week or so.