again, the idea of "adding muscle" with push-ups is not very likely.
Sure, it will certainly help build some strength in someone who is very deconditioned, and is a great tool for maintenance and increases in upper-body muscular endurance. But as far as adding muscle, I dont see the push up as a very effective tool for hypertrophy.
Effective muscle building comes from a very strict and well thought-out combination of exercise and nutrition. The general guidelines for a hypertrophy program are 3-5+ sets of 8-12 repetitions where the muscles are completely fatiguing within that rep range for each set, as well as after the entire exercise (completion of all sets). Again, unless someone is fairly deconditioned, it's going to be hard to reach failure by 8-12 reps.. Beyond those 12 reps, you're going to start recruiting more slow twitch muscle fibers and work those fibers (which are not conducive to hypertrophy).
You're also talking about a very specific rest interval with a hypertrophy program.
As far as the tempo, 224 or 103...the numbers are not magic! Whether the concentric is 2 or 3 or 4, and the hold is...whatever, they should be slow and controlled to put the muscles under a longer time under tension. But the specific count is not crucial.
You've also got to consider the purpose of the exercise; if you're doing push-ups as a general conditioning program, it is wise to vary, not only the grip (wide vs. narrow vs. feet on a bench...), but to vary the speed. How about adding some plyometric (explosive) push ups?! After all, the pec major, anterior delt and triceps (all of the pushing muscles for that matter) are often used in "real-life" situations as an explosive-type movement (shutting a car door, pushing something out of the way, etc...). So why not train this way?
Just some thoughts!
Wes