1. Where do you like to attach your tails on a Rev, and how many do you use?
I've tried them on the outer wing tips, which give great spirals in the tail from fast spins, but put a little wind drag on the turning controls.
Seemed to me that tails on the bottom tips tended to pull the tips together which exaggerated the leading edge flex to a point where I felt it impeded the kite's abilities.
I like the center best, since the tail drag there effects only the center drive and not the R/L controls which generates in the outer portions of the wings... Also, from a front view (as the pilot sees), the tail originates from where there is the least amount of sail, making it the most visible.
In theory, just on the main points alone, you could easily attach seven tails... Outer tips, top vertical tips, center LE, bottom tips.
Other places could be used of course, but these are seven pre-existing points that can carry the load and provide an easy place for attachment.
2. What type of tail do you use (tube, flat, plastic, ripstop, mylar) and in what width(s)/length(s)?
In my experience, tube tails provide significantly more wind drag compared to the flat tails... I prefer the latter.
The wider (larger) your tail, the more drag... Same goes for length.
I like 1/2" mylar (or ripstop as a second choice), around 50'... Longer tails make cooler spirals.

Ripstop tends to fray and eventually snag up on itself much more easily, whereas mylar is a bit more slippery which is good for less wind drag and snag ups on itself.
3. What model of Rev have you used with tails, and how do you feel it effected the flying characteristics of your kite(s)?
I've tried Rev I, 1.5 and II with tails, performance effect outlined in my response to question #1.
4. Any problems with getting your tail in the lines, and if so, how did you avoid it afterward?
Off the center of the kite, I've never experienced this problem, even in light wind.
Off the tips, I've occasionally gotten tails into the lines, but generally only in the lightest of winds.
5. What effect did it have on the wind range?
Depends a lot of type and material.
I'll be interested to hear what others have found with various materials in light conditions.
6. Have you flown team with tails, and if so, what new challenges should one expect?
I've only flown tails during a single demo with the Bay Area Sundowners (team with six 12-packs of Hypers, each kite with a 35' tail.
Because of the tails, spacing becomes much more critical as you have to try and avoid flying into the tails in front of you, and angle your flight path base on predictions of where the tails will be 3 steps ahead... Generally the tempo between turns expands, as pilots wait for the tails to clear their next flight path.
Can't wait to hear what y'all have tried and found!