Hi Alan,
Maria has been using the curved slider with a water bottle mount for the past year with no complaints. I just took it off her V20 because she wanted to test a long chainstay, and with that installed, she needed to go to a straight slider.
Here is a picture of her curved slider with bottle cage:
I agree your hands look a little high on the hoods. Before going to a curved slider, I would suggest rolling the handlebars down just a bit. You may need to re-position the brifters. I always wait to tape the bar so I can make adjustments after riding some miles.
When you say the boom "bottomed out" did the boom hit the tap for the cage bolts in the slider? I cut about 5 inches off the boom on Maria's bike. I can still use her boom and I'm 6'2", so no worries. The boom is made really long to fit really tall people, but feel free to cut off what you don't need as long as you still have a few inches for clamping. Just file the cut end to smooth the edges. It's really important to get the cranks, handlebars, and headrest all dialed in. You are on the right track.
Jim