If no LMB are present in the pond and if proper gravel beds are present and if good crayfish population is present you should have no problem with SMB spawning. With adequate food, I've had SMB spawn in a clay bottom pond; no gravel. Recruitment of young fish may not be real heavy but you should get enough every year or two to maintain adequate mixed sizes in your pond. Maintain minimal bass harvest and in poor spawning years an occassional supplimental stocking when necessary of 5 to 10 3" fish would not break the bank.
In the spring or fall of the second year (since the SMB prob will not spawn till age 3), I would consider adding 3 to 6 more SMB per acre.
If you use bgill as forage I am very interested in the outcome of this stocking combination. I know of no one whose is doing this, thus I am very interested in the results and management methods required to maintain a viable fishery composed of SMB and sunfish. Does lakedoctor have advice about this topic?