I have a 460, 0-15%, don't know for sure. I use it for windskate. You can try it if you want, it will give you an idea.
Since you mention RDM, I plan on avoiding SDM for 400 size and smaller. These get used by people I introduce to windsurfer and by my kids more than by myself (Light winds as you know...) SDM is impossible to grab for them!