Brother Rich,
please allow me to correct you a bit.
4 fingers on the 4 fret positions on a upright 42 1/2 scale is physically impossible for I think 99% of the bass players on this planet I guess. MAYBE (just MAYBE) a man as SC can do it -seen his giant hands- but even that I doubt.
If I learned my lessons well in classical upright class:
index finger = first note (A flat on G string)
Ring finger = second note (A on G string)
Pink = third note on (B flat on G string).
The 4 fingers on the neck starting at the A-flat and reaching to the B-flat with the pink is called the first position in playing upright.
My teacher of electric bass always said that he could recognize upright players with no formal lessons playing electric because they play with the fist = covering from a-flat to b-flat on an electric withfour fingers gives the impression to play with a fist because the scale is shorter and the notes closer to eac other.
Although the inverse is also true: when one studies electric bass you'll be learned to use your four fingers: one for each fret: starting at A-flat up to B.
Believe me: that is hard for everyone (except for the already mentioned SC) except our Brother and Alembic collectioner par excellence Rami who practices scales and arpeggio's on the Evil Twin and the Dark Prince which are 36 (yeeeeks to play but fabulous sound) basses one of them fretless.
So I would say: please play how you play your upright. It's only theory based on best practice experience.
Isn't there a bassplayer (Abe Laboriel?

??) who misses some fingers on his left (neck side) hand?? I am not sure.
Though I know that the Belgian/French/Gitane guitarplayer Django Reinhardt had only a thumb an 2 or 3 fingers left on his left hand. Ever heard what incredible voicings and chords he came up with? I bet that creativity is hidden in your wife too!!!
Well ...oh ...huh ...oin het BASSPLAYING I mean of course!
Paul the bad one