Sounds like you have the whole process perfected and I'm going to copy it unashamedly, including buying a ten gallon round cooler.
Does this scenario sound ok:
My first all grain batch will have a 10.6 pound grain bill and mash at 153F. At 1.2 quarts per pound of grain thickness thats 12.7 quarts, or about 3.5 gallons of water.
At a grain temperature of 85F, my BIAB calculator says I need to heat my strike water to 167F. This goes into my cooler with my grain and a good stir and final temp adjustment while I heat 3 gallons of sparge water to about 180F in my brew pot. This should get me about 6.25 gallons of wort pre-boil given a 0.25 gallon water loss to the grain.
An hour later I raise the bag and drain it into the cooler until I figure it's done, then dunk sparge the bag in the now 170F water in my brew pot. Let sit 10 minutes then raise bag and drain again. Start heating the sparge water while draining.
Take the bag out, add in the cooler wort to the brew pot... Voila! I'm ready to boil and then it's business as usual.
Do those numbers sound right?
(Look at me using all this impressive beer-talk language!)