Need help with water schedule

I am going to do a Founders Red Rye clone full boil with an estimated finished 11 gallons. I am using 13 pounds of grain with 8 pounds of DME. I am thinking I should do a partial mash using 13 gallons total. Start with 3 gallons steeped for 45-60 min @ 150-155 degrees. Then sparge with 10 gallons @ 155-160 degrees for 15-20 minutes. Have a couple extra gallons on hand to top off at the end if needed.

Opinions?

Use 1.75 qt./lb. for the grain. That would be 5.75 gal. rounded up. Sparge with as much as you need to hit your boil volume. If you're fly sparging, 15-20 min. is way too fast. If you're batch sparging, start the runoff slowly then open it up after the grainbed is set.

Is this an all grain batch? Where did you get those water amounts? Remember, you'll need water hotter than 150-155 in order to mash at 150-155. I'd recommend sparge water in the 190-200 F range.