Glad to help.
Go slow and repeat the technique over and over, concentrating on playing cleanly and consistently over several practice sessions. Just be patient. Then, and only then, speed it up by a little bit. When you’re good with that, speed up a bit more.
This is a process, not a one and done.
The good news is that this process will serve you in every aspect of playing. Think of it as learning how to learn. You got this.
How are you supposed to slow down triplets or sextuplets? I’m at a loss trying to practice them because when you slow something like that down it’s still double (Triple?) the speed of the rest of the notes.
Triplets usually just mean you play three notes in the same space as you ordinarily would two. It’s not that much faster.
For example, in 4/4, an eighth note triplet is played in the same time as two eighth notes usually would be (i.e. one quarter note).
It’s the same way you can recite the alphabet: You can say it fast, or you can say it slowly. It’s all up to you.
Similarly, the point is: You can play something at any tempo YOU CHOOSE, fast or slow.
For example, many players play a triplet by thinking the phrase “One-and-a” to ensure that each part of the triplet is of equal length and emphasis as the others.
That same “One-and-a” can be played quickly or slowly, just as you can SAY any word quickly or slowly. In other words, no phrase you can say (or play) needs to be said (or played) at a set speed. It’s up to you how quickly or slowly to express it.
Here is a lesson on triplets by Mark Smith of Talking Bass. Go to the 1:28 mark in the video to hear the beginning of his excellent explanation of triplets.
Tip: You can use the YouTube player control to slow the video playback as much as you need to be able to play the short exercises Mark demos. 
I can share an obstacle I’m on the struggle bus with.
It’s lines I can play, especially incredibly “simple” eighth lines that just chug… chug… chug… my brain feels like I’m losing time and it gets frustrating to where I get fatigued and start playing the quarters instead if I sense nobody is paying attention to me (lol)
Think: Paranoid, Runnin’ Down a Dream, Punk Rock.
When I get to 160 bpm+ it just gets rather fatiguing after a couple minutes. Maybe just a stamina issue, but curious if anyone adjusts their right hand for stuff like this? I’ve been trying out different ideas to relax my wrist/arm.
Losing time is where the drummer becomes your friend. Lock in with the drum beat and use that to keep yourself on time. I’m working on a 160bpm song atm and the advice I can give that’s working for me is to relax your shoulders, relax your plucking / picking arm, and make sure you’re breathing. Find a comfortable position where your wrist stays in a straight-ish position and chug from the elbow. Let that do the work rather than your wrist. I position my arm so that the pick is hitting the strings just behind where the neck meets the body. It still gets tiring after a few minutes but that’s stamina, and doing it more will build that up. Just don’t hurt yourself and keep checking in with yourself to make sure you stay relaxed.
The tone knob should be up at 75% or more unless you are going for a classic compressed tone.
I don’t know struggling is the word, but I guess it’s official - no more full scale or even medium scale basses for me. I hadn’t picked one up in a while, and with the new Offbeat bass I restarted B2B with a pick, and I did the first lesson, then after using Obie, I switched to Herbie, and did the workouts, and for kicks did the workouts again on my Bass VI.
After a few minutes I had soreness and pain in my left forearm, and then switched basses and did the next lesson. Pain went away. Picked up the bass VI, pain comes back.
Growing old sucks, but I am happy with the basses I have.
I’ve lost track of what scale length each is. The VI is long scale, and the other two are short scale?
The other two are short scale. The Vi is technically short scale with a 30" neck, but with the placement of the bridge it has a reach more like a long scale. Like the G&L Fallout
OK, that makes sense.
Do you still have any long scales?
I do. I have a Sire D5 with a Dusty Hill Pickup; I have a Fujigen Jazz with Fralins and an Audere preamp, I have an Ibanez EHB1500, and I have an Ibanez Mike D’Antonio sig bass with a Harris pickup
It’s still preferable to not being able to play at all. I’m glad you can still make it work with a different scale.
I bought my zoom b1 4 from an older gent and he said he loved bass, but his shoulder could not handle it anymore. He would stick to playing guitar. I did ask him if he was sure he would sell and not perhaps buy a short scale and try it first and see how he faired, but lucky for me, he had made up his mind.
100% true!
Since I switched to my beloved short scales I have no shoulder issues anymore, whatsoever. Even my “usual” non-bass shoulder issues are disappearing now (slowly!).
Maybe I’ll get younger too, due to playing short scale??! 
It could happen.
My new bass weighs less than my guitar. When I picked up my Mustang bass after playing the new one, the stang felt heavy. And its not
Going to keep chugging as long as I can