Brewing Big RIS, Please Help!

[Hoppocrates]

So I am planning on brewing a Bourbon County Stout Clone with an O.G. of 1.120. I have done a lot of reading and realize that my efficiency will be terrible but to recoup some of that wasted sugar it is best to partigyle and brew another beer. So now I am planning on doing a Russian Imperial Stout and American Stout partigyle brew. I searched partigyle here on hbt and google but am still confused...

Looking at Mosher's article (http://www.brewingtechniques.com/library/backissues/issue2.2/mosher.html#3) I am planning a 1/2 - 1/2 split giving me a total batch O.G. of 1.0910 and a split of 1.121/1.060.

Ok, now what do I do to calculate my brew session?
About my setup:
-batch sparge
-hopville to calculate recipes
-brew365 for mash/sparge water
-ezwatercalculator to build water
-62 quart cooler MLT so space is not that much of a constraint

Do I now simply calculate my recipe for the RIS by setting my mash efficiency to 60% and then adjust the thickness of the mash to give me all mash water and no sparge water, which in this case is 12.25 gallons of mash water at a thickness of 1.5?

And then for the second batch just sparge with 7 gallons of water for the American Stout addition?

Any thoughts are much appreciated...

 

[Hoppocrates]

No one?

 

[CaptYesterday]

So you're planning a no sparge RIS and an American Stout with the residual sugars?

As long as that 12.25 gallons covers the grain absorption (~.1 gal / lb grain), equipment loss, and trub loss in the kettle I think you're set. The 7 gal sparge for the lesser stout should get you ~7 gallons out for that beer.

Your strategy seems sound. Let us know how it goes.

 

[Hoppocrates]

So you're planning a no sparge RIS and an American Stout with the residual sugars?

As long as that 12.25 gallons covers the grain absorption (~.1 gal / lb grain), equipment loss, and trub loss in the kettle I think you're set. The 7 gal sparge for the lesser stout should get you ~7 gallons out for that beer.

Your strategy seems sound. Let us know how it goes.

Thanks, was looking for some reassurance!