Javier: That's the way I'd do it. I would probably run the shim out a couple inches, to make sure the joint doesn't have a kink in it, then taper down to the roadbed. I had to do that quite a few places on my layout, because the ME flex and handlaid turnout ties weren't always the same height. Also, snce I used both C55 and C40, every compromise joint had to be shimmed, and those were done the same way.