Re: Telecaster low E buzz
2mm at the 12th fret is already fairly high. It should be able to sit there with no buzz I would have thought?
If its buzzing, then It's not high enough.
Your ears are a better measure than anything else. Let them guide you, but dont worry too much about fret 12 to start with. Dont worry about how high they are before you fret them because there is another super important part of the equation (the truss rod) which we will sort out later.
Set the action so the upper frets (like 15 and up) are noise free under your regular pick attack when you fret them(some players play harder than others). Especially the frets from the body join up. Do this for every string because they all form different size ellipses when played at their pitch. You will find that the Low e needs a lot more room than the high E and the one sin the middle all need to work their way around the curvature of the neck. You may need to have the action a little higher if you find that bend notes on the high frets start to "fret out". YOur ears will let you know when it gets too low.
Once those are done, tighten the truss rod until the guitar plays evenly across the entire neck.
You may find that you can get your action lower than it is currently and be rattle free.
This is all assuming thats the frets are all dead level and dont need a fret dressing (which you said is the case).
Last thing...make sure you use a proper fender shaped truss rod tool because they truss rod adjustment nut is easy to strip. You can find them on ebay etc. Also make sure that there is no string tension on the neck when you tighten the truss rod. Never adjust more than half a turn and then let it settle one in tune for at least half an hour. Right is tight, left is loose.
