Number of LMB stocked depends on your goal. For large LMB 50 per acre or less. For balanced pond 75 is plenty. However with large GSF and BG stocking 2 inch LMB may be problematical. If you could get 40 (total for your pond) 6 inch LMB then that may work better.

Question why stock tilapia if no predators (LMB). If so then you better watch your biomass with the tilapia.