I would stock the GSH this spring and get them spawning. In all likelihood, they'll die out in a few years anyways. Until they do though, they will add a little extra to your forage base. Then your orginal stockers will die of old age and that will be the end of them. Few ponds that are steeply sloped and under a couple acres will produce self sustaining GSH populations under reasonable LMB predation.

I would stock no more than 25 HSB and probably keep it closer to 10-15. Then you can add a dozen or so each year after. Make sure you stock advanced HSB later on as the LMB get larger in size. Otherwise they'll just be expensive LMB food.