I have yet to move on to practice cards as well. My logistics issue is that I have 29 kids in homeroom and 35 kids (with only about 5 from my homeroom) in reading. Our reading block is 120 minutes and seem to be with these kids more often than I am with my home room!
What I have found to work out OKAY w/o the practice cards yet (they will come in due time...) is keeping those kids in for recess for 1 - 2 minutes and have them repeat the rule they broke for a minute, including the gestures, followed by a brief talk to make sure they understand why their choices were foolish.
Also, if I find myself frustrated with the whole class and just need a break, my old system was "HEADS DOWN" and wait for silence, then start my timer and deal with kids snickering, sneezing, coughing, tapping, etc. Now...., the whole class stands up, I set the timer for 1 minute, and the class as a whole repeats which ever rule I feel they have been breaking. This gives them the opportunity to get up and move a little bit, which they clearly need if they are having issues focusing and it gives me a breather.
Also, maybe try implementing more frequent rewards...kindergarten is so young and need immediate reinforcements...Maybe every 1.5 hours you evaluate the scoreboard. If the happy face wins then the class gets to sing a 30 second silly song or watch a youtube clip of babies laughing....something quick.
Hope that helps.