This is what one of our member moderators (Theo Gallus) says about SBS.
"If you are referring to Jonesfish, "Specklebelly" (SBS) is what I believe they are calling their BGxRES hybrid (based on their webpage and the conversation I had with the young man from Jones who treats one of my ponds).

I love my BGxRES (developed naturally from male BG and slutty RES females as opposed to purchased). They do indeed take very well to pelleted fish food. My current record is 13.25" long and a little over 2 1/2 pounds.

They have one negative that may be of importance to your pond - they will breed in higher numbers than RES (although not as high as straight BG). I suspect you will have insufficient predation to keep their numbers in check with just 12 HSB. I have breeding populations of YP and SMB in my 1/2 acre pond with RES and BGxRES, and remove 400-500 BGxRES annually to (try and) keep their numbers to what I consider optimum. (I feed fairly heavily, and about 1/3 of these are eating sized.)

As with all hybrids, subsequent generations are not a pure BGxRES, but random mixes of these two sets of genes. This has caused variation in appearances but no noticeable negatives or problems in my pond (my first BGxRES appeared in 2008, so I have had several generations of grandchildren and backcrosses with RES).

We do not swim in this pond, so I cannot comment on whether BGxRES will "nip" at swimmers as BG, but not RES, are sometimes complained about doing. FWIW my family has never had a problem with BG "nipping" at us while swimming in our other pond. (Perhaps we taste bad.)"

IMO I would wait until you have your other fishes established and doing well before adding SBS. If they have offspring that becomes mature the genetics could over several generations revert towards the more prolific specie which would be some sort of F generation of BG. If you decide to use Hybrid crappie HBCP, I would not stock SBS because both would be producing wide bodied offspring that could become too prolific that would require LMB as population control which may be okay for your goals. LMB would eventually eliminate or make the YP a very rare fish.