I'll make a lateral suggestion - do a quick sample (10 - 20) then work from there, creating paths where necessary. Trying to reconcile that many different users
a) will take a very long time
b) is unlikely to be reconciled into a logical, easy to manage list
and c) will need to be adjusted later anyways
Support file search path is stored in a single registry entry ("ACAD") under the AutoCAD profile as a semi-colon concatenated string. Its one of the easiest items to tease out of the structure.