From what I can tell, Everything may have some support for this later on, but for now the recommendation is to use the "-server-share-links" ETP link type (\\server\C\sharedfolder)
The issue with that is of course having to share the entire C drive (which can be controlled via NTFS permissions to limit access but still leaves the issue of having to remove/unshare the administrative share "C$" so that the share can be created again using only "C").
There are two ways I will suggest to overcome these small obstacles:
1. Use a symbolic link or junction by using any of the following programs (choose one that is suitable for your OS), junction.exe / linkd.exe / mklink.exe
The way to set this up would be to have a folder on the root of let's say the D: drive. Let's say this is "D:\CustomerReports\" and you have an instance of Everything indexing this folder and will allow users to connect to it via ETP.
Next, we can share the CustomerReports folder and label it "D". Now, use the junction / symbolic link program to map/create a new folder called "CustomerReports" within the existing "D:\CustomerReports" folder.
As an example, using linkd.exe
The syntax for linkd.exe is "linkd.exe <SOURCE> <DESTINATION>"
We would use this command, then:
linkd.exe "D:\CustomerReports\CustomerReports\" "D:\CustomerReports"
Now, you should have this new folder, mentioned above the command, created.
As a whole, what this has done is shared the original folder as a drive letter (D), then once the user searches Everything within the original folder, on their own machine, they will access the share itself (called "D") and then within there they will "hit" the dummy folder that will then link them back to the correct, original folder.
This method is a bit messy as you create a share with the name of a drive letter but at least don't need to share the whole drive. You are not limited to only sharing one folder via this method as you could create a folder called "EverythingSharedFolders", share this folder as the drive letter "C" or "D" or whatever and within this folder make your actual shared folders and create links for each one. Note, that there is no sharing of the "real" folders, you just share the parent folder and then would need to control access via NTFS in this scenario of having a central folder.
2. Use the "substitute" command, or "subst.exe"
This method is a lot simpler and much easier to manage as all you are doing is mapping whatever directory you want to index and share with Everything to a drive letter on the server itself.
A. Use subst.exe to map a shared folder to a drive letter that is 1. available/open on the server and 2. will be the same letter used for the users to map to (This is the key to this method working, the drive letters must be the same).
B. Have Everything.exe index the new substituted drive letter on the server (don't index the original folder, just the new drive letter.) This could even be done via the NTFS area, as the drive letter will be treated as a local disk.
C. Map the client to the same drive letter and connect to the Everything ETP server from the client using the "drive-links" ETP link type (W:\)
That's it, the user will now be able to access the folder because Everything is showing whatever it sees within the (substituted) local drive of the server, which cannot be accessed normally of course, but the client is able to due to the mapped network drive connection which points to the original folder, so the client really doesn't have anything to do with the substituted drive letter; it is there simply to let Everything index it so it can be accessed easily.
Well, hope that helps someone! Again, I don't know if this has already been suggested in the past, but I didn't find anything so hope someone finds this via some search terms.
