Least amount of water for 5gal partial mash batch?

trying to follow deathbrewer's method for partial mash. The problem is i have an electric stovetop and can barely get 3gal of water to a rolling boil. With my last batch of extract i did much better at around 2.5gal and topping off to 5gal.

With his method, he used 2gal of water per 5-6lb of grain to mash. He then used an additional 2gal of water for the sparge. I know there is going to be some evaporation, but when you combine the two for the boil, its probably going to be at least 3.5gal.

Can i use less water for the sparge? like a gallon? so my total is at around 3gal. or should i modify the recipe and use less grains so im only mashing in 1.5gal of water?

Also, does it matter which pot you dump into the other? He dumped the mash pot into the sparge pot? wasn't sure if there was a specific reason for using one or the other.

If you use less sparge water, you'll get lower efficiency, but it will still work fine. If you're not fixed on getting _exactly_ 5 gallons into your fermentor, you can do the math and figure out how much to dilute your partial boil as you move it.

Doesn't matter which pot you use.

You'll also lose some water to absorbtion, which is probably as big a factor as evaporation, but exactly how much depends on how big your grain bill is.