Here's my understanding of cylinder deletion in a nut shell.
We delete/deactivate cylinders to reduce pumping losses. The pumping loss is reduced because we open the throttle more and less energy is required to drag air into the engine.
Only 4% of the engine loss is due to pumping loss (
See This) so it isn't like you'll double your mileage by eliminating it.
So now you gotta ask yourself a few questions.
Can I live with less horsepower if I delete cylinders?
Can I delete the cylinders effectively and maintain optimal performance in the remaining cylinders? Doesn't do you much good to delete only to have your engine management system try and compensate for a running condition it was never programmed to operate under, consequently yielding worse mpg. I really believe this elephant sitting in your sandbox is greatly overlooked or never considered by peeps talking cylinder deletion.
How much time effort and energy are you going to expend doing this for what payoff? Ya really gotta consider the cost benefit analysis of all this.
Factory attempts to deactivate are better and more sophisticated, but these require deactivation on the run, which I pray you are not wanting to attempt. Even still the benefit is not huge by doing this.
I know it is sort of a stretch, but variable valve timing is actually a back door way to limit the displacement of the engine, you sort of deactivate a percentage of all the cylinders in order to reduce pumping loss. Again, factory engineered schemes here not meant for the common man to attempt to modify on your own car.
Anyway, all this is just thought exercise, I'm 99% certain no one has ever done a homemade cylinder deactivation and gotten outstanding results from it, power decreases immensely, the engine management system would hate it and need to be modified to the point of causing madness, and you may not see any gain in fuel efficiency.
Hope this helps you understand, or maybe give you other things to look into.