BillD. - you advised to stock additional predators to handle BG population issue. The stunted 5" fish are already in the pond given your scenario: BG population issue - that's the impetus to stock more predators! These are slow growing adults - and a few will continue to run the gauntlet, and are anywhere from age 3-9. It's a bottleneck situation, just like LMB can do at 8-10" or 12-14", etc. Since these 5" BG aren't vulnerable to predation, their population stacks year after year with no management - bottle necked at that size range. That's 5-6 years worth of BG, all stunted into the same size range, tying up biomass and utilizing forage which could benefit desirable species. That's what the predator density solution will render - one cannot just stock more predators, it's not that simple, and that's why this solution alone isn't going to be effective. Further, all those predators now densely stocked have no forage and WR drops so you have zero quality fishing for any species. That's the scenario we're trying to help the forum avoid - through direct experience. The solutions are complex and depend on multiple variables.
So, we're back to the original advice: Managing BG population in a limited gape fishery requires significant management through angling, trapping, seining, etc. in order to be truly successful as a higher quality fishery. Stocking additional predators in my experience can have an impact on the population, but it will also tax your pond resources and can result in low WR predators as well. Doubt that is the goal for any fishery.