3 qt/lb is on the high side, but should be fine provided the temperature and pH are in range.
I'm not sure how you arrived at the pre-boil volume, but apparent grain absorption is 0.12 gal/lb, so assuming there's no dead space (and there shouldn't be for BIAB) you'd only need to mash in with 7.2 gal to get 5.95 gal pre-boil. You could use less if you're planning on squeezing the wort out of the bag.
FWIW, lauter efficiency for 10.5 lb of grist and 7.2 gal of strike liquor would be
~75%.