sure,
basically the problem at hand is that currently in zbrush if you want to create an entire character with a lot of detail you cant because of the poly limit in Z brush, so you have to save off your character in seperate pieces so that you can further divide them and get the poly resolution that you need.
The problem with this is now when you load each of your pieces there are different min/max displacement amounts per piece so when you calculate all the seperate maps and them apply them to your mesh and render them in your 3d package there will be seams between the pieces because the different displacement maps have different ranges of displacement being represented in the greyscale information.
So the fix I have here is to manually define the min/max amount of displacement on each of your seperate pieces, that is why there is a seperate piece of floating geometry assosiated with each piece of the mesh, so you can use the max amount of Zadd and Zsub with your brush (which is 100) and create kinda of like a clamp on the displacement values, so now all of your pieces DO HAVE the same min/max amount of displacment
hope this helps some, if you have any specific question just let me know and Ill try to make it more clear, I admitt its kinda wierd and there are a lot of things to keep your head wrapped around
the reason for keeping the extra row of uv’s from the nieghboring piece is that if you dont Z brush will streatch the UVs and you will get wierd streching between each of the pieces
of coarse with the promises of Zbrush 2.5 this may become obsolete as you are allowed more polys per mesh but I suspect you wont be able to have single meshes with 20+ million polys which sounds like more than you would ever need but if you look at scan data that is used from sculpture you will find they are well in that range for capturing all the features of the character.