Marko, I think the 16th note count is really 1e&a, 2e&a, 3e&a, 4e&a. I may be wrong, but playing those note patterns at 168 bpm on a Tuba sucks so f'in hard.
An absolutely essential song for 16th note practice is, Hit Me With Your Rhythm Stick by Ian Dury and the Blockheads, so iconic is the bassline that the video showed Norman Watt Roy's left hand on the fretboard, super imposed over the rest of the action. Norman can also be heard on every Frankie Goes to Hollywood song, check out Two Tribes for instance. Don't be put off by Rhythm Stick, it's not as hard as it looks
One of my all time favourite bass lines, don't feel ready for it myself yet.
I just decided to play with a pick. I hate playing with fingers so much
Nothing wrong with that. There are definitely advantages to playing with a pick, but don't rule finger playing out completely. For every song that sounds great with the crisper tone provided by a pick, there are just as many which benefit from the softer tone provided by finger playing.
Also, believe it or not, there's going to be a time when you're jamming with your band (or, worse, playing a gig) and your pick's going to go flying. There you are, in the zone, chugging away, then suddenly VROOP, your pick's off and flying like a fart in the wind (and it will happen – happens to everybody, even the most seasoned pros). Sure you can grab another one from your pick strip (if you have one) but if you've developed your finger playing skills, you could recover without missing a beat.