Partial Mash Water Volume

Looking at an IPA recipe (partial mash) using the grain bill listed below:

• 4.0 lbs American Two-Row Pale malt
• 0.75 lb American Crystal 60L malt
• 0.75 lb Belgian Caramel Pils malt
• 4.0 lbs Briess Amber DME

Per NB’s Partial Mash Tips, “For every pound of grain in the recipe, collect 1 quart of water in the mash kettle”…Does that mean just those grains being steeped in the mash water or does it also include the DME (post sparging addition). Put more specifically, do I use 2.75 gallons of water in the mash for the first 5.5 lbs listed or 4.75 for all the grain?

And if you bear with me further, NB’s Partial Mash Tips goes onto suggest the sparge water should be the same volume as the mash water. If this is accurate, I’m going to require a bigger boil kettle than the 5 gallon one I currently employ.

Thanks

The mash water is just for the grains. The mash works to convert and extract the fermentables from the grains. The DME is later to provide the remainder of the fermentables. DME and LME come to you already mashed and ready for the yeast to ferment.