To set the initial respawn times, go to the logic_auto then set "OnMapSpawn > tf_gamerules > SetRedRespawnWaveTime > [parameter] (And red can be blue) ... the parameter is the seconds of the respawn wave time.
You can also do this for any other output command, like OnCapTeam or something. Just, change it through the tf_gamerules.
Respawn wave times are a bit weird. If you set them to like, 4 seconds, that team would spawn between 4 and 8 seconds.