HELP NEEDED MR BEER Partial Mash - A steam lager called "DON'T RUSH to judgement"

As many of you know, I procured 4 MR BEER Kits for cheap.   They were an overstock item.  I have never made a MR BEER kit.  I don't really plan on making a MR BEER kit.  Although I am a fan of their equipment.  2 gallons is just about the perfect size for me.   And unlike my other fermenters,  the LBK fits perfectly in the fridge for cold crashing, and lagering.

My favorite lager yeast is 2112 from Wyeast.  You probably know this yeast as California Steam beer yeast. You may have been told that it is a "hybrid" yeast.  Some weird variety that is not really a lager and not really an ale. In truth it is in fact a strain of saccharomyces pastorianus, or lager yeast. It is just a lager yeast that was mutated many years ago to create a lager yeast that could produce lager characters at ale temperatures.   

There are some issues with 2112.  It is not a perfect panacea for people wanting to make lagers, without lagering equipment. The aa% (apparent attenuation) can be a little low.  (But that is true for all lagers).  Here is what I have found;

• You have to aerate the heck out of this.
• You have to pitch an adequate amount of yeast.
• Although it should work fine up to 70 F. (21 C)  DON'T DO IT. It works fine at ale temperatures, not at room temperature.  So use a wet t shirt (swamp cooler) , or put it in your fermentation chamber.

That being said.  I just can't bring myself to throw away the MR BEER extract. I know it is pre-hopped, but... good barley gave their all for that extract. And now that coopers is making it, it is just Cooper's pre hopped extract. So I'm Going to do a 5 gallon partial mash in my electric turkey fryer.  This beer isn't super hoppy, so I am going to chill it down with ICE. The idea here is to show MR BEER guys that they can make a great beer with the ingredients that came in the box, a 5 gallon fermenter, and less than $20.00 of additional ingredients.    

ASSUMPTIONS (and this is where I need your input)

• MR BEER American Light is pre-hopped so that it will create about 12 IBUs in a 2.25 Gallon batch.   So if i double that, I will get 24 IBUs in a 2.25 gallon batch.   But I am making a 5 gallon batch.   So that means that I have to account for this.   
• 24 IBUs of SAAZ (which is what they use) is equivalent to 1.3 oz in 2.25 gallons.   
• So 1.3 Gallons of Saaz in a 5.5 gallon recipe is 16 IBUs.  Right in line for the style I am brewing.  Premium American Lager. 
• Am I thinking this through correctly?   Both Beersmith and Brewtoad seem to think so, but... Come on guys did I miss anything here.
• I am assuming that I can just follow my normal partial mash process, but Mr. Beer kits are no boil so... Am I thinking Correctly

Let me know what you think.   My recipe is here.

But it is basically
2 # of Pilsner
2 # of 2 row
.3 # of Carapils
.5 # of Corn Sugar
and 3.74 of MR BEER LME
Wyeast 2112 yeast cake.