Having worked for Specialized, I know a bit about the Romin and Romin Evo.
The Romin Evo has a narrower nose and softer padding. Overall the fit should be the same as a Romin despite the different look ie if you ride a 143 Romin, then a 143 Romin Evo would be the go.
Both the Romin and Romin Evo (curved saddles) are however, effectively narrower than a Toupe or Avatar (flat saddles) so just because the ass-o-meter recommends a 143 saddle based on your sit bone width, doesn't mean that's the width you'll definitely need. I ride a 143mm Toupe and a 155 Romin Evo, my sit bones measure 118mm on the ass-o-meter. If your sit bones are over 120mm I'd highly recommend trying the 155 version of either Romin. I can explain further, but essentially the curved design of the Romin is more curved side to side as well as the front to back shape so while the outside widths are the same, the effective area you have to sit on is narrower on these curved saddles when compared to the flatter Toupe.
I to prefer the Evo as especially in the 155 width, the nose of the regular Romin felt intrusively wide. The softer padding feels nicer also.
Regarding the Toupe and Avatar -- which has the flatter profile? I'm talking side-to-side (i.e., when viewed from behind), mostly.