Cloning drives for older CNC machines

We have a number of CNC machines all controlled by a normal desktop PC. The oldest is from 2001, the newest is just a few months old.  These mainly use Win XP, but we also have Win 2000, Win 7, Win 3.1 & Dos 6.0

We keep a spare PC for each machine pre-configured and ready to switch over should we have a problem. 

 To make sure these spare PC’s are up-to-date, once a month, we remove the hard drive from the machine and spare computer, make a clone on a stand alone and then put the spare PC (with the cloned drive) in the machine in the belief we have two identical computers.

The stand alone PC is kept in the office and used for nothing else. We boot off a Clonezilla CD to make the copy.  The motherboard has IDE and SATA connectors so we can use any type of disk.  We don’t use a USB caddy but would this be ok?

Problem is, Clonezilla is a little complicated to use and recently we have had a number of failures, trashing both hard drives so are now looking for a simpler solution but it must be 110% reliable.

Because of the old operating systems we have to use I’d prefer to still remove the drive from the machine for cloning.  Is Ghost a good tool to use for this and are we using the best method? 

Thank you for your help,

Dave