I will have a 6th rig with 2 cards in it used for testing, modding the bios, etc from the main groups.
That's a good idea. A lot of new miners don't have a dedicated "test rig" and it's not usually missed until you start having problems with your main rig(s). That's when that extra rig comes in handy, you can swap the components between the failing rig and this test rig to quickly figure out what the cause of the problem is.