I think I've noticed something in your reasoning about tennis. It seems that you want to spend Y amount of dollars for X amount of tennis, while the rest of us spend X amount of dollars for X amount of tennis. Your willingness to make an effort to reach 5.0 in three years or so, while it usually takes ten or more years is noble, but it doesn't make a "tennis unit" cost any less. What you will save on for your efforts is years of being stuck on plateus.
The amount of drive and initiative that you show turns up on the other end of the equation as giving your body a beating with dead poly. I think you have to decide either to spend more on the intense amount you're training, or play less. Playing less wouldn't be a bad option. It would keep the sport fresh for you, anticipating your next court time. It's like over-playing your newest CD, instead of spreading it out over the years.
Dunlop MuscleWeave 200G 95, SEARCHING FOR A NEW MAIN STRING / Hexy Fiber 16 @48/53, dropweight stringer