Then I got my first 4001, and soon after put a set of Rotosounds on it, to get that prog bass sound, a la Squire. My drummer complained my tone wasn't bright enough (through my B-15) so I started playing with a pick. First I used a Carol Kaye pick... which is a smallish tear drop shape. Then I used a regular shaped tortoise colored celluloid Fender heavy pick. I used those style picks for 20 something years. I used to pick so hard I would break them!
To stop breaking them I switched to the Dunlop Tortex picks... the purple ones (1.2 mm... I think).
I went through a period where I got away from the bright prog bass sound, and played with flats again. I was going for a warmer sound, so after about 26 years of playing with a pick, I simultaneously switched to a 5 string and my fingers! Talk about feeling like I started playing all over again!
Nowadays I mainly play with my fingers... but lately I started using a pick occasionally. My picking on bass is not as good as it once was, even though I have also played lead guitar all these years. Now I use a 1.2 mm Clayton pick for both guitar and bass,,, But mostly I use my fingers, and often just my index finger.
it's like being able to only use one finger
The important thing is to alternate your picking! Don't just use down strokes. I almost always start a run with an upstroke... I'm not sure why, but that's how I play. Also when alternately plucking with my fingers, I start off with my ring finger.

