I'd call Mitutoyo tech support...
As for the scale/head alignment - it's pretty much the same principle for all scales - mount the scale so it's true in both axis (shimming etc may be required), then the same with the head. There is normally a specified gap between the head and the scale. You need to use a dial indicator for both - the spec is pretty tight...
Until you get the exact info from Mitytoyo, go to Acu-rite's web site and download theirs - the process of scale mounting is well documented and will let you know how to approach it.
On the BP.. the long table scale is easy. it's normally mounted on the rear and secured to the table a few thou above the saddle. The table is straight enough so all you have to do is get it mounted true WRT the saddle (or the table top). The head mounts to the saddle, needs to be true to the scale, and usually needs shimming.
The short table scale/ head... same idea but there is a bracket for both.
The Knee - ha.... PITA. there is no flat mount surface so you have to create one. I maded 3D adjustable mounts on the column for the scale and a three bolt attachment (floating) for the head (on the knee). The scale is set by DTI off the knee way.
All scales I've used have detachable ends - you take on end off and slide the reader head out ( very carefully). The dirt is usually on the rubber seals, and they are suppoed to just pull out. However.. time and coolent take their toll - they will likely be swollen or hardened and may not come out, and if they do, may not go back in.
