I use this pattern: I wouldn't worry about being exact too much, unless you really need it. In either case a script would be the best way to go about doing this. It will be MUCH faster over the long run. EDIT: If you don't have a script another way to do this is find a single face that you can scale precisely (perhaps…
I've made a script that visualises it, blue is too low res, red is too high. It's only for Unity but I'll post it later anyways. Perhaps someone can make a maya/max script out of it. I don't have acces to my computer right now.
Doesn't UDK have similar visual tools? Or is that just for shader complexity and not pixel density? You might be able to set the desired parameters to match your stats and just drop the things in UDK. MoP's normalization script idea that was rolled into TexTools was also added to 3dsmax2012, its called "Rescale Elements".…
A manual way to do it would be to make 1 x 1 meter plane and map a 64 x 64 pixel texture to it where you can see the individual pixels clearly. Then map whatever size texture you need with the same pixel pattern onto your objects and scale your objects UVs until the pixel patterns on the two objects match. A better way…