beau, I very much like your rings the way you showed them last, with the diamond band on the bottom and the plain on top. I wore my original rings that way for years and years, and I never got tired of the look! If you have the finger length to handle the widths of the three rings, then I think they look great together! The two bands look the same width, and I like that. I do think the e-ring shank could be thinner, but that is just personal preference. I, too, hope you'll consider keeping your diamond as a solitaire because you have so much more flexibility that way!
Your set looks great, I also think that you should leave it as is...I think you would miss all the playing around with different looks that a solitaire allows!