You want to keep LMB on the smaller size and numbers numerous to emphasize predation on crappie. In the beginning, I would harvest LMB over 15" long. Release all LMB below 14". This will result in more pounds of smaller LMB in the standing crop, cause more bass numbers, and put strong predation pressure on crappie 4" and smaller. You only want a few crappie each year to move into the 5"-7" size category. The few that make it will have ample food to keep growing. Don't forget these crappie (often predators) will have to compete with small LMB for food so there won't normally be lots of food (minnows, large bugs) for good growth of both. Larger crappie can feed well on large zooplankton and LMB can't. Thus the few crappie can grow if there arn't too many. After 3-5 yrs, if you are seeing good sized crappie (8-10") then you can bump up the slot harvest to 16" fish and see how this affects the average size and body condition of crappie. IF things aren't working and crappie are all smaller than you prefer and thin bodied then move slot harvest to 12". Harvest all 12" LMB and return all healthy smaller bass.
IMO LMB will be a better and more efficient predator on smaller crappie than HSB. Them mouth of an HSB is significantly smaller than a same sized LMB. To prey on crappie IMO you want a big mouthed predator to eat a little bigger crappie to emphasize or capitalize on the predator standing crop and its predatory efficiency.
Although if you need some angling diversity you could add 15-25 HSB per acre especilly if you have lots of open water spaces. Unless someone knows better, I don't think it will make much difference which LMB subspecies you use - northern, Florida, or tiger since your goal is not producing large bass; just numerous bass.
