Thanks for the feedback so far, greatly appreciated!
#3 was probably my favorite image out of the whole day, even though it may not be a "technically perfect" shot....you can see that it was shot through the chain link fence behind the backstop, and even at f/2.8 I couldn't completely get rid of it.
This shoot gave me a whole new appreciation for those of you who are proficient at sports shooting - it's a fast-paced environment and I missed focus on a number of shots as I tried to simultaneously switch subjects and zoom to get my framing right....got a few "great" pics of blurry fielders and razor-sharp fences in the background!
Back-button focus was a huge help - I tried both ways, and liked the versatility of the back button vs. using the shutter button for AF.
Jeff - I definitely had a few issues with tilt, but didn't notice that one until you pointed it out - thanks! Had my share of cut off feet, bats, tilted horizons, etc. as I flailed around trying to catch everything I could. I was surprised by how much DOF I got at f/4, too - I thought it would be fairly shallow even at 70mm, but I wasn't able to isolate like I thought I would. I just punched the numbers into the online DOF calculator and saw how wrong I (obviously!) was.
I want to thank all of you who have posted tips here and in the "Sports Talk" section. I did a search and spent hours before this shoot reading all the threads containing various tips, tricks, lessons and sample photos, and it was a tremendous help.
Here's one more image for consideration:
