XNormal is free, I have it also, so there is no reason not to at least have it.
As for the question about polycount on character. I expect my character to be in range of 100k triangles. Its not a big deal as I am making an adventure game, & she is the only character you ever seen for most part of the game, & only in cut-scenes.
You need quite a bit of triangle to break the edgy look of a character, hence the high triangle counts in many next gen game character
Some screen caps on the character model I am working on. (note some are Zbrush high poly sculpt for normal mapping), but I expect similar level of details after normal mapped. I hate to admit it, but I am pretty please with the shape of the character butt I made. 
://img.photobucket/albums/v211//Locked%20Room/CaptureAliceWIP03_zpsb1a2ed0c.jpg
://img.photobucket/albums/v211//Locked%20Room/CaptureAliceWIP05_zps2ea5aea3.jpg
://img.photobucket/albums/v211//The%20Locked%20Room/CaptureAliceWIP07_zps07708848.jpg
As far as how much to use, I think in the end, its a factor of how much overall polygons you have in your scene. Since I have low characters count on screen, I can dedicate more polygons on the character. If you have a big epic battle scvenes, with hundreds of character, you probably have to restrict the poly count on each character on top of using LODs.
Anyway, I base of the polygon budget of my character on next gen game like Ryse, order, killzone.
Since my game will not be release until at least 2016, I I go full next gen, in terms of visuals, & performance. Also the reason for using Unreal engine 4. Having a cutting edge, realistic look compare to other of adventure genre (which still mainly have 2D backdrop, or stylised visuals at the moment), is one of my (hopefully) selling point. The next being badass gameplay.
Anyway, about the Order, as much as I love the look, I always thought to myself…“Looks so good already, just imagine if it used UE4!”.