CA 1's real-time processing is occurring in the application programs address space so it is processed with the priority of the job. There is nothing to set in WLM for CA 1 specifically.
When CA 1 is reading/updating the TMC, the task is marked non-swappable and once the update is complete the task is marked swappable again. So the internal processing of CA 1 during realtime execution would not be affected by altering the priority of the job(s).
While TMSAPEC and HealthChecks are running under the CTS address space, the TMC is enqueued for the first 1000 DSNB's being read from the DSNB free chain pointed to by TMSCTL#2. After the first 1000 DSNB's are read, the TMC is dequeued and all work after that is done in the background.
Altering the tasks priority would be not beneficial in this process either.