This is my suggestion after going to dozens and dozens of Dr.s for years. Also, was told this by an RN,....my mom.
You tell the MD what you would like and why. Firm but kind. Then if he refuses and puts you off you kindly ask that you would like it on your record that you requested this and it was refused. Also saying that you will get a second opinion.
Congratulations on deciding to flush. I came to curezone 4 years ago and was too afraid and sceptical to flush for all that time. Only after an attack and the thought of getting my GB taken out did I do a flush. It was easy and amazing. At this point I have nothing to loose.