The little screws serve two purposes - the vertical ones adjust how high the string sits above the fingerboard at rest - known as the 'action', and the horizontal ones (in the same axis as the string) adjust the intonation - allowing the player to stay in tune all the way up the neck.
If a string is rattling too much when it's tuned properly then chances are it's bouncing on the metal frets and needs to be raised - the vertical screws will do this.
Puts me in mind of Keef getting schooled by Chuck Berry...
...the clip seems to have disappeared from YouTube, but suffice to say that Chuck was NOT as gracious an instructor as Ms Kaye was.
I've had great fun watching the 12" driver (admittedly, it's designed as a sub-woofer) in my 'Bass' cab jump backwards and forwards like billy-o until I start to raise the frequency of the HPF and then it doesn't move anywhere near as much. Still sounds great though.
Seriously, every home should have one!
Just finished up building and boxing an F Deck high pass filter and can honestly say it's a real game changer through my Ampeg rig.
Most of the time what it does isn't audible, but speaker excursion is visibly reduced, meaning my rig is operating more efficiently than without it.
Wow.
The difference between the crybaby and the bass version is indeed the 10nf (0.01µf) to a 68nf (0.068µf). a 47nf (0.047) will get more low end, but a 68nf will be better. It certainly won't damage anything.
The major Influences on my Dad's side were the Beach Boys and Dire Straits, my Mum is a Queen fan, so it's all good in the hood.
Along the way I picked up thrash metal, prog rock, disco, funk, Jazz etc...