If your sole goal is to feed the HSB a supplement other than the pellets, I would stock golden shiners over BG, even if there are some bigger LMB. The LMB will hammer your GSH as well, but unless you stock some really tiny BG, HSB in the 8"-10" range are gonna have a hard time preying on them... FHM would be another option for 8"-10" BG, but would be way to easy a snack for you already present LMB, so I would stick with the GSH.
