I use a G40 all in one, and have always been frustrated with the amount of little bits of grain, etc, that escaped the brew basket and made it to the boil. No matter how course I crushed, this was always an issue.
Now I have used the 400 micon bag on the outside of the basket and did my mash...no more bits of grain, now only hop particles from the boil remain. I have just ordered a 200 micron bag to use when I boil, to keep those bits out of the fermenter as well.
Highly recommend to take your wort to the next level.
Great writ up on BIAB, you really touched all the bases and addressed the common myth’s that some say is a knock to this method. I have been doing BIAB for over a year and I love it. I have been building my recipe’s at 80% efficiency and have been getting that and better.