Done it as well and it works fine. Switching to AG and properly calibrating my thermometer has eliminated the need for it for me now though. I was previously having issues with my extract batches stalling at 1020 and my first few AG batches mashing too high due to the thermometer being off by...
All-Grain, Partial-Mash, or Extract? BIAB AG
*If All-Grain, what is your estimated efficiency? 75%
*Boil time? In minutes 90
*Will you rack to secondary? no
*Hop Pellets or Leaf? don't care
*What is your start boil volume in gallons? Have a keggle so can be up to 10 gal
*What is your end...
30 qt will limit you to a 3 gal batch unless you do a Maxi-BIAB.
http://www.biabrewer.info/viewforum.php?f=89
Also, you can use the spread sheet in the recipe section to scale a recipe
http://www.biabrewer.info/viewforum.php?f=7
NRBs All Amarillo APA was my first BIAB (scaled to a 3 gal total)...
X2. I use the BIAB calculator and it has worked well for me. I just added an extra column to convert the metric units to pounds and ounces.
http://www.biabrewer.info/viewtopic.php?f=7&t=15