This might help... First make sure the bass is consistent with itself. Just solo it or whatever and make sure the notes are all around the same level. If not, there are a few ways to deal with it:
First, you will want to hi pass the bass at 31 hz (in most cases- most subs don't produce below 31 so jt saves headroom to cut). Next, find the fundamental frequency of the root bass note (for E this is 42 hz I believe, etc). You can find it online with a google search for frequencies of musical notes, or use a sweet app called MusicMath if you have a Mac. One you know the fundamental, go to the 2nd order harmonic on an EQ. For 42 hz, this would be 84 hz etc. Cut this frequency to taste (2-4 dB usually for me) with a shelving EQ. What this does is reduce the fundamental note, which is usually the boomiest due to buildup. This should be pre compressor, so that the excess energy you're removing doesn't cause the compressor to pump excessively. One nice way is to use a compressor with fastest attack and fast to mid- fast release and a high ratio, then just lower the threshold till it's taking about .5-4 dB off (check gain reduction meter). This tames any quick spikes that are left over after reducing the fundamental. After this, if the material calls for it, you can add a little additive EQ to bring up any frequencies that might be useful in filling out the mix. Make sure you are not soloed if you do end up deciding to boost. After this pop on yet another compressor, this time with a lower ratio (1.5 - 3), slower attack time (use your ear, preserve the attack) and the longest release you can use without biting into the attack of the next note. If available, use a compressor with character for this part (either some analog emulation or change mode to opto in stock logic comp). This adds some roundness. So basically that method is first correct, then enhance.
Alternatively, you can cut up the bass by note and then level them with fader automation. After it's level that way I'd bounce it to a fresh track and then you can use a chain like what I described before. You gotta bounce so the rides are pre fx (and therefore won't cause the comp to pump etc).
Once you have made sure the bass is hitting evenly then take it to the level where it sounds right to you. Then put this on an MP3 player or burn it and check it in the car. Note how loud the bass is. Compare with some pro mixes in a similar style. Then bounce out some alternate versions of your track, one with the bass level dropped by 2dB, one by 4dB, and label the tracks as such. Go test these in the car, and record which one sounds best to you.
Now all you gotta do in the future is mix the bass level how you want it to sound, and then drop by the amount of dB that was best in your test before the final bounce. Eventually you can hear it when the bass is just right in your monitors.
Let me know if this helps or if you are confused about any of this!