Crane,
I run SBB on all of my hives, I have also added them to my nucs this year. In the south, SBB's can bee really bad. I have found over 400 in the dry oil tray of one large hive, I suspect it had swarmed. As I have said before, when I started out, I was killing SBB's by the thousands in all of my hives. Every month I would clean out the oil trays, they would bee solid black with SBBs. After a couple of years of me and my neighboring beeks doing that, the beetle numbers dropped so low that we stopped using oil and ran them dry.
One of the great things about oil trays is they not only kill the beetles, they also kill the larvae when the craw out of the hive to pupate. They drop into the oil and die. This stops the breeding cycle of the beetles.
When you get to the point that you can run them dry, bee sure to clean them out once a week during the warm months. The larvae that get removed by the bees can grow in the dry tray by eating the dropped pollen.
Btw, the larvae can survive in the tray if it just has water. You need to use oil to kill them.
Jim