What would you consider that number to be, and what size LMB should I look for?
Size and number of LMB really depends on 1. how fast you want to get small fish numbers reduced; 2. what sizes of small fish and really the specie you want reduced.
Remember the LMB IMO will be first consuming or targeting the more slender bodied prey as the biggest sizes that LMB can capture. Obviously IMO an 8" LMB will quicker eat a 3" YP compared to eating a 3" sunfish when both 3" the YP and sunfish are equal numbers. With using the LMB in your pond's current fishery, Plan on the YP population to be more quickly reduced compared to your sunfish in numbers in the panfishes. If it were me I would make some current catch written records from simple angling methods and sessions using worm/bobber and compare al that are caught over the next several years (3-6) then you will be able to better evaluate how the LMB are impacting the fishery balance from now into 2028 - 2032.
What do you expect the LMB to be ultimately doing as far as reducing fish sizes and density in 2027 and 2028? What are the
sizes of the most abundant fish you want to remove??? All this info will help with providing better advice for sizes and numbers of LMB to best be stocked. Remind us as to pond size and water clarity.