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) and it turned out well.
I respectfully disagree. I just did a BIAB AG batch last weekend using a 7.5 gallon turkey pot and a full boil. I had an 11 pound grain bill. Notes below.
1. Double crush the grains unless you're sure the mill is set to a fine setting suitable for BIAB.
2. If you're doing more than 7 or 8 LBS grain in a 5 gallon paint strainer, recommend you double bag the grains (bag in a bag)
3. Mash at 1.25 Qt/lb
4. heat water to strike temp. dough in and stir until all the grains are wet and the mash falls to your mash temp. Mr Malty is a great resource if you don't want to do the infusion calcs yourself.
5. Cover, set timer for 1 hour and go do something else. I have an oven thermometer with a W/P probe so I can keep an eye on the temp without lifting the lid.
6. If temps fall below your mash temp lower limit, put the heat back on LOW and stir until they get back up. I was suprised how long the covered SS pot held temp before I added heat. I believe at 30 minutes I had to add heat and stir for about 10 minutes or so.
7. Drain first runnings into a convenient container, squeeze the P(*& out of the bag. Rubber gloves help prevent burns.
8. Heat sparge water to strike temp. Measure first runnings and heat enough water so the 2 total about .5 gallon above your target into-the-fermenter- quantity. That accounts for boiloff. For me boiloff was .5 gallon because my electric stove does not acheive a strong boil and the turkey pot is tall and narrow. YMMV
9. When the strike water is up to temp, turn off the heat, pop in the grain bag, cover and wait 30 minutes.
10. Lift and squeeze the P^%$ out of the grain bag, return first runnings to the pot and boil as usual.
11. At this point I usually take a SG reading and add DME to ensure I hit my OG. Some will say I am not a true AG brewer. To them I say pthhh. I'm the only one that drinks my beer, I'm the only one that has to be happy.