Rimshot, here's my opinion for what it's worth.
There are no starting points to use because of so many factors man.
1. The bass used
2. The player and how they execute (meaning, how hard the pull, fretting, cleanliness, sloppiness etc)
3. Pick, felt pick, fingers or pop/slap
4. The action of the bass
5. The pick-up height
6. Is the sound driven like Dean's or smooth like Jeff's
7. Amount of eq used (example, more low end will require more compression the same as more high end percussiveness. The more smooth and neutral, the less compression)
All the above stuff will dictate how to set your compressor. For someone that knows how to play, you'll need less compression. For example, in Jeff's piece, I'd guess the ratio is probably around 3:1 taking a wild guess. You can tell the bass sound is beautiful and what *I* personally strive for in my bass tones. No drive, it's clean, it's precise and there is enough percussiveness in the tone as well as good low end that works with the kick drum. (excellent mix Jeff)
In a sound like Dean's, the drive usually adds some compression to the sound so you may not need much...however, some feel the need to squash the sound good for effects purposes. I personally do not like driven bass sounds like that because to me, they just sound un-natural and like a bass synth. That's no offense to Dean...it's just not a bass sound I like when people come to me and go for something like that. It is a common sound of "today" though...but the compression used will depend on how you (Rimshot) decide to drive it. That said, he's nailed the "now" bass sound and has done it well to where it's not sub low and a problem child. (Well done Dean.)
Now, if we had a pop/slap type song going on, everything in the game changes. You will use way different attack, release, threshold and ratios on a bass like that. There is so much force on a pop/slap that the eq plays a vital role in the outcome as well as the compressor. So as you can see, it's near impossible to even have a starting point for any of this because there are just so many variables that make up a bass sound. It's just one of those instruments that is a per experience type of deal in my opinion, Rimshot. Best of luck.
-Danny