I completely disagree. I don't think knowing the note names really helps with reading at all. For me, it's knowing where each note is on the bass that I use way more often than what the name is. When I see a note on the bottom line of the staff, I think "3rd fret on the E-string (or 2nd finger 1st position since I'm originally trained in classical urb)". While I obviously do no the note I'm playing is a G, is doesn't really matter at the time I'm playing it.
+1
Ultimately, reading music so we can perform that music is the process of translating a location on the staff into a location on the bass, quickly. I dont get the approach of injecting other concepts into to the process...ie intervals, and lines and spaces. Yes, one does need to know the note names on the staff, so just memorize them cold. Why do you need mnemonics? its not like you are memorizing human anatomy!
When I am reading a chart in a big band or a pit orchestra, and the performance is flying by, my brain just needs to know bass clef, top space, and "G" (wherever you decide to play it...open, 5 fret D string, 10th fret A string and so on...). I suppose in the back of my head, the morsel of information that I am playing "G" is floating around, but it isnt on the front part of the brain (metaphorically speaking).
The absolute best way to learn reading is to just read as much music as you can. Start out with very simple exercises which focus on low positions, first on one string, then moving across the finger board, then add notes up the fingerboard. Any good beginners bass book by MelBay or similar would work. Heck, you could get the Simandl method for acoustic bass. Book 1 starts out with such exercises, just ignore the fingering and positions, they dont apply to electric bass.