RT,
With the 1911, you can use the external hammer and compression to retard slide velocity. Not so, with a striker fired gun. That leaves you with recoil spring/assembly, slide weight and barrel compensation.
Don't know whether anyone is doing threaded aftermarket barrels, but one with a comp would be the most helpful. A heavier weighted RSA is a must, to at least get you started. Been playing with a Glock 41 myself, and the consensus and what I have witnessed is that with my Glock, I can easily and readily see impacts with the polymer frame abuttment point, where the slide impacts. With my 41, a heavier spring gets me to mid-level Super. It takes the comp to go low Rowland.
If anyone makes a shock buffer for the XDM, that might help, as a disposable, to help the frame. I tried this in my 1911's with the Rowlands, but they got chewed up very quickly.
There used to be a Rowland discussion board, and I do remember some talk of "what about the XDM for the Rowland". If that is still around, there might be some thoughts.
And I guess my last thought is about case support. If you are going to run with the stock barrel, the case support, or lack thereof might be your limiter.
Craig