Here is a simple double decotion that I have done quite a few times now. It's the only way I do it anymore. It boils almost all of the grain. You could even drop the mash out or use an infusion mash out for a single decotion.
If you want to do a protein rest dough in at 130, rest ~20 minutes. Infuse to 140-145 rest 20-40 minutes.
Pull most of the grain out with enough liquid to maintain a rolling boil (this is what gives the efficiency gain by gelatinizing and releasing more starches to the mash.) No need for any rests it will finish conversion in the next step. Boil 10-30 minutes. You have to mash thin so as to keep most of the enzymes in the liquid still in the mash.
Add this in slowly to hit 155-160 (add the extra after it has cooled.) Rest 20-40 minutes.
Last pull most of the liquid and Boil 10-30 minutes. Add back slowly to hit 168F. I cool the rest of the decotion with ice so I can add it in quickly.
Changing the times and temps can make about any fermentation profile. This is nearly the same schedule that I use with a cereal mash.