I hope they're working well for you. I haven't changed anything lately because like you said, once you change one thing everything goes crazy. But here's my 2 cents...
First, let me preface this by saying that I don't really test on odd numbers (6, 67, 23, etc). Everything on mine is multiples of 5...just weird that way.
QBA 6...should be fine, I play with the Saints so 5 is working for me. I agree that you don't want to go too high with this because passing becomes too easy for human and CPU
WR Catch 67...Haven't tested above 50, originally started this at 45 but had a ton of drops. Worried that putting it this high will cause the WR to "suction" to the ball and catch everything.
Run Block 3 or 4...I personally couldn't get anything to work other than zero. Running game seems to even out after a few games.
Int 23...Again, not too far off. I'm not seeing many picks right now at 25, but if you're throwing or picking off too many then lowering is the right thing. I like it at 25 because the CPU will usually make you pay for an errant throw.
Fumble 3/4...I am actually thinking of moving this to zero as well. Been reading whosnext thread and his thoughts are very similar to mine.
Overall, I like how you tailored them to your liking. No set is gonna be perfect for everybody but I think these are a good starting point.