First partial mash and first all grain coming up

Alright so I am jumping ship from the extract and specialty grains to the partial mash and all grain BIAB but have a question about water volumes. I have done 6 extract brews that have all turned out great but like the flexibility of the more complex methods and the cheaper costs.

I have been reading everything I can find on techniques for both and see different info about sparge water volumes. I would like to do a full boil to avoid top off water if possible because no matter what I read it sounds like top off water is a bad idea for the quality of beer.

Do i need to sparge with the amount of water needed to get to my full volume after the mash or do I sparge with a specific calculated volume based on grain bill and add the rest of the water volume to the wort before boil, or something completely different?

I am doing 5 gallon (post fermentation) batches (6.5 gallon fermenter) so I am shooting for around 6.5-7 gallon boil volume in my 32qt turkey fryer pot with an immersion chiller for cooling.

The partial mash recipes I am doing are the following:

christmas ale:

6.00 lb Light DME
1.00 lb Caramel/Crystal Malt - 40L (40.0 SRM) Grain 7.50 %
1.00 lb Wheat Malt, Bel (2.0 SRM) Grain 7.50 %
0.50 lb Special Roast (50.0 SRM) Grain 3.75 %
0.08 lb Roasted Barley (300.0 SRM) Grain 0.60 %
2.75 oz Hallertauer [4.80 %] (60 min) Hops 34.6 IBU
0.50 oz Cascade [6.30 %] (10 min) Hops 3.0 IBU
0.50 oz Cascade [7.50 %] (5 min) Hops 2.0 IBU
1.25 oz Ginger Root (Boil 5.0 min) Misc
1.50 tsp Cinnamon Stick (Boil 5.0 min) Misc
1.75 lb Honey (1.0 SRM) Sugar 13.13 %
1 Pkgs London Ale (Wyeast Labs #1028)


IPA:
http://hopville.com/recipe/1388832/imperial-ipa-recipes/blitzkrieg-hop

All-grain BIAB is a left hand milk stout clone from austin homebrew that is going to turn into an irish car bomb stout.

Any help is much appreciated, please dont kill the rookie for asking rookie questions.

BIAB is pretty easy. First thing to consider is the water lost to the grains. I've gone with this chart for a while, using an estimate of about half the amount listed as loss.

http://www.brewmorebeer.com/water-lost-in-spent-grains/

Reason being that if you use a bag and can find a way to hang it for a few minutes after the mash you lose a considerable bit less than with a normal mash/sparge. As for a sparge, I'll usually heat the mash to about 168 for 10 minutes at the end to make the sugar more soluble, and then rinse the bag with a gallon or two of warm (not hot) water when it's hanging. Overall efficiency is not too bad, generally in the 65-75% range, occasionally 80+ if I'm lucky.

On a note with the boil volume, starting with a 6 gallon boil for an hour will net about 5.25 post, so you may be looking too high to start with, unless you plan to boil for some while longer.