Dave, I agree with Dave, don't worry about the aspect ratio ( a standard 5X4 would probably even work). I often use the Maxpreps ratio of 2166x1600. It works quite well for most size prints as long as you leave just a little room around the edges.
The images are very nice captures. Obviously, your whites are pretty hot in the first but you can deal with that in post if needed. On the second, I'd probably use both the shadow and highlight sliders to lightly tweak things as I think you could tone down the highlights and lift the shadows slightly. Otherwise, great work out of the gate and glad to hear you enjoyed shooting sports!