I had the same issue after breaking my rear ankle. I have a double vapors and just put a heel wedge under the footbed inside the liner. I believed it was helpful for getting me back on track.
For a RTP there are a couple of good options. If you have access to extra pad material (similar to what is the footbed on your existing RTP), bevel it and add to existing pad to get desired lift. You could also take some binding rubber (or any kind that's not slippery) for that matter, and glue it to the plate. Sand/ shape accordingly. Aquaseal would be a good adhesive.