I've had an OSP for nearly a year now.  I bought an RMRcc the same day I bought the OSP thinking it would fit the slide cut, but of course, it didn't.  FWIW, I was new to RDSs at the time and hadn't done enough research going in.  Regardless, I liked the RMRcc so I bought the Trij adapter plate and have been carrying it since then.  

As time goes by, I'd really like my optic to sit lower than it does with adapter plate.  

Am I crazy to be thinking about having my OSP slide milled for the RMRcc as opposed to buying a Hex Wasp and putting on it?

Either pay to have it milled or go with a 507k which takes a lot less precision to mill and you can do it yourself in no time.

But if you like the optic then sure...pay to get it milled.

But the slide was already milled by HS Produkt/Springfield. This would be a highly unusual modification. Have you fully thought through the implications of modifying the slide? What if the gunsmith ruins your slide?

Why not just get a different optic or suppressor height sights? Like what about the Shield RMSc? Or the Holosun 507k? Or anything else on this list: https://www.thearmorylife.com/top-5-hellcat-red-dot-optics/?