I'm using your version 4.0 sliders all the way except I lowered cpu power to 5. I believe they are 15/25 and 27/15 I changed cpu to 27/5 because of the HR issue with the cpu.
"I thought you liked them at 0/0?" - Your post asked what slider sets are people using to get balance between CPU and Human. I'm saying there is no slider set that will do that. I suggested 0/0 but I'm not using them because I was playing MLB for the past 6 months. My timing was off. However, it's come back and my philosophy is that once one learns how to pitch and hit and master's the meter, the CPU is at a huge disadvantage. It can't compete unless you go up another level like MVP and even then you'll eventually become to good for the CPU. The only choice one has is to make the sliders harder for the human...thus 0/0. Six months ago, I was using -50/0 human and 50/50 cpu plus -50 pitching meter and 0 for cpu control, -50 human control. If sliders did what they say they do that is contact and power I should have been creamed by the cpu. I typically won 140 games no different than if I played with your sliders.
There are two schools of thought at conflict here: Use sliders to simulate realistic baseball, which you try to do or use them to reflect personnal achievement and challenge. If you become too good at hitting then why not work your way to a 0/0 set for human? If you become too good at pitching then why not work towards -50 meter for human? It may not be the perfect simulation but it reflects that you've mastered the game.
If you truly want a great baseball sim then try MLB06. It does sim more like baseball and makes MVP look like an arcade game, which by the way it is. That's why once you become good at it, the human will dominate the CPU.
MLB06 in my opinion is not as fun and takes over and hour to complete a game.
Anyway, your doing exactly the thing I did which caused me to try MLB over MVP and that is spend too much time on sliders and not enough time enjoying the game even if you find winning too predictable, enjoy the game.
Good Luck and stay in touch.