I was only able to be on the protocol for 17 days because the baby came early. My breasts had increased a full cup size, but were not 'heavy/painful' either. I did as Lalle said and stopped the bcp the day he was born and started nursing him with the l/a. After 3 months of nursing with the l/a, I was able to stop using it, as I had a full supply.
Good luck and keep us updated. Also I would try to meet with a lactation consultant as soon as you can to help with latching while using the lact aid. This was probably my biggest challenge.