I always use the paper method to check mesh, and once you learn what a proper mesh sounds like then you can go by that. to check if its meshes properly take a slip of paper and run it in between the clutch and spur and then thread it out.
a good mesh will be a bit tighter than what is shown in the pic below
You dont want any rips or extremely sharp angles. the pic above is too loose in my opinion. you shold be able to see a small space from where if fully meshed all you would see is teeth against teeth, also if you hold the clutchbell you can jiggle the spur a bit back and forth.
As far as the sound it makes, when its tight you will hear a louder chatter, when done right you still hear metal on metal, just not as loud. I use the paper , the space I can see and the sound all to help me achieve a proper mesh.
As far as the slipper goes most trucks and etc are different and I have never ran what you own. but generally for off road bashing you tighten all the way down then back off anywhere from 1/2 to 2 turns, and then adjust from there. If you are going to set your slipper it is better to err on it being too loose than too tight. as it being too tight will ruin drive train components.
Mind you I am no professional, this is just what I've picked up while learning over the last few years.
The last consideration is if your clutchbell isnt shimmed properly which will cause it to move forward and backwards on the drive shaft. make sure the is little to no movement of the bell on the shaft, and if there is add shims. the most important thing is to make sure it always spins freely with no resistance.
