A few notes: depending on how extensive your local wrecking yard is, I use identical manual mirrors from a Plymouth Sapporo (functionally identical to Dodge Omni). I also replaced the glass front 1/4 windows with plexiglas/Lucite and DRILL BOLT HOLES in it to positively hold the mirrors on.
Gluing things onto glass is a black art due to the molecular layer of water that forms on all glass surfaces milliseconds after you thoroughly scrub them clean . Temperature changes also affect glue bonds. Simple to make cheap lucite quarter windows at home, and they can be tinted at home as well. See articles in the POCA Archives. They are also 4 lbs lighter than glass.
Note also- I needed a pair of shims between the mirrors and the window in order to correct the viewing angles. My shims are hand-sculptured wood (nature's composite), different for each side and painted flat-black to match the mirror bodies. Angle-shims complicate gluing even more. In a stock Dodge Omni, there's a flat steel plate spot-welded to the door, and the mirror is bolted to that, just clearing the Dodge glass window.
If you insist on electric mirrors and you can't find electric Omni's, BMW 318 mirrors along with a hand-built angle-shim for each side, have also been used. Good luck.