I have had success introducing them into my main 3 acre pond where LMB were already established.
Here is a
Dedicated to RES thread about a new pond build that was dedicated to raising only RES (page two in the thread is where consideration of stocking the SMB started). But a year or so into the project, based on some positive experiences Shorty and NEDOC have had with RES and SMB combinations, I added SMB as fingerlings. The fingerlings did great and in this pond without competition from LMB and reproduced to the point I had a lot more SMB than I needed in this one acre pond.
So I transferred a bunch as 6" fingerlings into a sediment pond and forage pond to raise up big enough so my LMB in the main 3 acre pond could not eat them then at 9-12" transfered to the main pond. I also transferred some 9-12" directly from the RES one acre pond into the 3 acre main pond. I'm probably around a total of 50 fish transferred to date to the main pond over the last two years.
The SMB take to pelleted feed easily (I do feed both ponds) and grow quickly. We now catch SMB in the main pond along with the LMB that were in there all along. So I will tell you that stocking 9"+ SMB in a pond with already established LMB has worked very well for me. A friend caught one out of the main pond that was just over 4#, so I would say they are doing just fine.
I had another big spawn SMB this year in the RES/SMB pond and am thinking about transferring a bunch more to my sons one acre pond later this fall. They are a fun fish to catch.