Even though it is more difficult to manage the KiX version it should be much quicker if you copy and run KiX32.exe or WKiX32.exe from the local workstation and then run the script from the NETLOGON folder. Removal of the /F switch would increase speed at the cost of an InGroup call maybe not detecting the users credentials in the group because they had been added to the group less then 30 days ago by default. You could also specify how many days to refresh the cache - 30 days is the default.

If you really don't have to run some code for remote users you could also copy a file and time it to determine their connection speed and then take action based upon those results.