Help, Cecil, Help!
CB1 may have the best idea on growth rates. If you have an idea what size RT you might start with, post it.
6-8 lbs LMB should make a good go of cleaning up slowly dying RT in the Spring. I suspect the remainder of them won't hurt a thing. They'll get cleaned up by "Mother Nature's 4-legged Cleaning Crew" as cold-water killed Tilapia are always reported to.
If/when I do a Winterstock of RT, I'm going with my fish supplier's minimum order for the first year as a trial. This is 50 lbs. of 1-3 lbs RT. I have a 1 acre pond.