Christilou, I ran across two portrait photos I took with the Leica Elmarit-M f/2.8 90mm lens. I know you've already bought a 90mm lens and you're doing well with it. But here are a couple of photos for the future reference of others.
This first one was taken with a Leica M8.2. It wasn't made in a studio setting with studio lights, but I think it's better than the second one. That's the ex-girlfriend, by the way.
This second one was taken with studio lights and all, but it's not very well composed. I haven't spent much time using this lens, so I haven't learned how to use it in as a portrait lens. I took this one with my Zeiss Ikon film camera. So I wasn't sure what I would get. It takes time to learn a camera and lens combination, especially with a film camera. She's a friend of mine, in case you're wondering.
This is interesting, I bought the 90mm 2.8 because I didn't want a too sharp lens for portrait but I wondered if mine was a little too unsharp but yours seems to render in much the same way. I much prefer the first, mostly because it fills the frame but also it's not posed. The warmer colour is also much more flattering The 90mm is quite difficult to focus but I do have the advantage of the Olympus EVF to fall back on!
Here's one I took a little while ago, it was taken in tungsten light and I just couldn't get the colour to my liking (the M240 seems to be gaining a reputation for being a bit iffy in mixed lighting although it seems fine in normal outdoors daylight). Anyhow, I gussied it up somewhat. I go back to it from time to time in Lightroom but just can't get the colour right.