Your bowels will still be working on the juice/veggies. I would suggest continuing to take #1 and #2 during the L/GB phase as well. But as Dr. Schulze is not totally consistent in his directions on this point, if you can't get IF#2 or a pectin/bentonite clay combination, still proceed. Personally for me, I have to stay close to a bathroom when I'm on the juice phase. Things seem to run end to end in me on a relatively short transit time. Of course, that is just me. Your experience may be totally different.
Don't stress about this. The program which ever way you proceed will be good.