Follow up on this. Since I was retaping the Derosa bars, I played around with the brifter position, as some suggested. I was amazed at how big of a difference it made for my comfort by moving them up a little bit! I rode around a bit testing various positions on it, found one that felt most comfortable, and locked it in and taped it up. Feels MUCH better to ride it now.
Also, I see a few mentions on the seat level. How can I adjust it to make it more flat? They each have two bolts that hold two brackets that go over the seat rails. I have them both making full contact with the rails, which to me seemed what to do to make it stable. I see that I can loosen the front one, which raises the nose, but wouldn't that make it less stable and somewhat bouncy?