"The high profile Romeo 5 is primarily intended for use on a long gun."
This is something to seriously consider.
Many red dots are built with a purpose in mind. And if you try & put a dot designed for a long gun, that was built to be easily used when you shoulder it,, on a handgun,, problems can arise.
In USPSA,, long ago,, many of the "Open" class gun (which were the only ones at that time that allowed dot optics) users quickly discovered the perils of aligning the dot, only to find the gun sits too far below the dot & hits a wall, hard cover, or otherwise doesn't go where you wanted it to go. I have wooden walls with bullet holes in a port window frame because of this. I also have wooden walls where a shooter trying to lean around and the dot is on target, but the bullet impacts the edge of the wall.
Basically, you should always try & mount a dot as low as possible because of alignment with your eyes & the target on a handgun. Just as you try & get a rifle scope or dot to be in alignment with your eyes when the gun is shoulder mounted.