I think the key is having multiple options available to them. GSH is only a part of it.
As for the BG, the smaller SMB may eat some BG but I don't think the larger SMB mess with them. Maybe if it's all they had to eat it would be different but I don't think the growth rate would be near as good. LMB may/will utilize BG much more often.
I had a 4.5lb SMB in a tank indoors for awhile last winter with a few 12-14" smallies and 22 wiper of 4-6".
When I pumped water down I had 3 wiper left...

Cody note - A 4.5 lb SMB is close to 19.7" long. 1/3 the length of 19.7" = 6.5". A HSB has a more narrow body depth compared to a 6" BG and would be easier to swallow. FYI - Body depth of a 6" HSB is 32mm and body depth of a 6" BG = 60mm. Which would you rather swallow whole?


However those 4"-6" HSB are likely better faster swimmers than BG, but in this case all the fish were in an indoor tank which makes them easier to catch compared to if all were in a wide open pond.