There are really only two options for you.
1. You can get an adapter plate that replaces the rear sight in the dovetail. This will be the cheapest, most inelegant solution. It will have the RDS sitting up high.
2. You can have a gun smith mill the slide to accept the RMR directly. This can be done by companies like Black Box Customs et al. This will cost in the neighborhood of $300 and will look the cleanest and you may even be able to retain the use of your rear sight.
BONUS OPTION, You can find a pistol that is optics ready, not to sure which decent 1911s come optics ready. If you have your heart set on the Sig then option 2 is the way to go.
Also, how do I get free 1500k supercharging and what is free 1500k supercharging? Do I need it?
EGW has the adapter plates. I never had a rds on a 1911 but I want to try it. I figured the adapter plate is the way to start, if you like the rds after a few hundred rnds, then send the slide to be milled.
There is another option, frame mounted adapters, still need permanent modifications to the frame. Typically for cmore sights.
How about this mounting option? It has 1/3 co-witness. Will this sit lower than option 1?
https://www.trijicon.com/products/details/ca428-c-600759
The supercharging refers to buying Tesla. If you use my referral code you get 1500 km. Thanks
What’s EGW?
I have RMR on my glock-19 and I love it. That’s why I want to put one on my new upcoming gun.
Btw, what’s the time for transfer these days when you buy restricted from a store?