Physically I have a blank 100% ANSI layout. My keyboard is the Das Keyboard Ultimate 4:

Virtually I have set the “English (Macintosh, ABC, ANSI)” layout on my Linux system:

As quick start, I can press AltGr+` to put a ˋ on the next letter I type, AltGr+E for ´, AltGr+U for ¨, AltGr+I for ˆ, and AltGr+N for ˜.
Sorry for the late reply, hope this still helps you/someone.