Bucker
I have the yellow tape but have never been able to use it. It is to thick.
How you will know is when you thread the bp back into the barrel it should go very smoothly and evenly. If it get caught or is real tight the tape is to thick.
Clean the BP threads and the barrel threads. Install the BP bare - it should turn in very easily - when you put the tape on it shoud turn in almost as easily - right to the point where it stops.
I use white tape on the Knight Disc and Pink on the Remingtons and the White.
When you get done shine a light down the muzzle and you should see the tape all the way around the bottom of the barrel.