Since I did not receive any replies, here are my thoughts. If we could take 5 samples from different Heat numbers, and split each one in 4 specimens, then we could actually perform a gage RR 5x2x2.
Never heard of it!
But I would imagine the process to be similar to performing GR&R on any other testing equipment.
Your process seems sound (because it has to be random, but thorough), but it would also depend on company policy. Maybe you need more, maybe less, maybe a different process altogether.
If you were just told "hey perform a GR&R on this" then go with your gut
