Problem with low yield Cracked Corn & Red wheat mash

[Due51]

I recently picked up a large, 20 gallon vessel in an effort to make a 10gallon all-grain, no cook mash. Yesterday was my first attempt:

12lbs cracked corn
10lbs cracked red wheat
11 gallons boiled water + 2 liters hot backset.

I put the corn in the vessel and covered with 5 gallons boiling water + 2 liters backset. Covered and let set for about 2 hours.
Cracked my wheat, added to the mash, and added 6 more gallons of boiling water. Stirred for 10 minutes and added my first enzyme. Temp was about 180degrees.
Covered and let set for 4-5 hours, stirring occasionally.
When temp got to 150 degrees, I stirred some more, then added my 2nd enzyme.
Covered and let set overnight.
When I checked this morning, the temp held around 140degrees. I took a sample of the clearest liquid and only got a SG of 1.040

I'm reading an article on Wiki about Starch Conversion, but does anyone see anything in my procedure that would cause poor conversion?

Thank you.

EDIT: Welp, I may have found my problem. In the article there is a diagram of different gelatinization temperatures. Wheat gelatinizes at 125-150. Corn gelatinizes at 144-170. Maybe I should have put my wheat in my 5 gallon igloo cooler and poured 140 degree water/backset over it and let it set.