If he doesn't like how you play he should never have given you the job in the first place.
I commonly use just index finger ( and a second finger only if I really need to).
Otherwise I'd reserve 'two fingers' for the guitarist.
If those are both 34" scale instruments then the frets are identical distances apart. 17" from nut to centre of 12th fret. You need a tape measure not a photo taken at an angle.
If they aren't identical then you've been sold a pup.
I got a Supro 2042P Huntington bass, two pickup version, in natural mahogany with a piezo under the bridge. Here's Dood's review of the single pickup version, followed by a review of the two pickup model.
How is it a Lynott tribute? I don't know much about him and certainly don't wish to tribute him. Didn't he play a black Precision with a mirror pickguard?