Arc - As the late, great Douglas Adams once wrote, "don't panic"
I have always had to use plumbers' tape for the buttons on my PSE Intrepid and Border Talisman risers. I'm not sure exactly why, but I think it can be attributed to the fact that manufacturers obviously work to different tolerances.
As for the limb bolt issue, this is one of the hazards of a modern target recurve. Sometimes, you will find that certain set ups (bracing heights, stabilisers etc.) just seem to resonate at the right frequency to nock things out of line. I had this problem with my target set up (Intrepid + Border limbs) until I found a chose a new string material, a new bracing height, a good tiller setting and a decent set of stabilisers (Beiter). Each small step made things better, but the whole package is what was required to calm things down. Now, my bow has sounded quiet since the day I bought it, but obviously something wasn't right. Now it is, and I don't need to worry.
Obviously, this is not something people who shoot traditional bows will have much experience of. It's just an everyday hazard to a jaded target recurve archer.
The only thing I can suggest is that you experiment with a few different bracing heights and maybe string materials too. If possible use some dampers, but arguably these may just cover up a problem rather than solving it (so some say, anyway).
As for adjustment, the limb bolts are designed to be adjusted with the help of two hex keys of the same size. Place one in the bolt (on the back of the bow) and one in the retaining bolt (in the belly of the bow), and hold the one in the bolt firm while you turn the other to loosen it. Then simply wind the bolt in or out as desired (letting it rotate freely), and then lock again with two hex keys by again holding the bolt firmly in place while you tighten the retaining bolt.
Hope this makes sense. Sorry for the long post.