I’m interesting in knowing if my month old C5 has the “REST 5” option you mentioned above, I don’t see it? I too would love to be able to pause a protocol without having to start from the begining or turning it off/on. 
@NoWiFI I just toggled thru the protocols on my C5. Nope. There are 28, but none of the ones with the 5 minute rest period are there.
The reason these pulse protocols are on the M1, but not on the C5 is that both systems use the same microprocessor. But the M1 is a simpler device (only one output channel) so there is still some room for extra pulse protocols in the available memory.
But the C5 is a much more complex device to control (4 output channels), so there is not enough memory for the extra protocols.
The next logical question:
Question: Why remove the protocols I want, not some others?
Answer: Because the ones I chose to remove are the ones that are the least popular. So much so that some people in the past have actually requested to have those removed.
General design guidelines that I follow:
I include every option that is possible, ranked in the order that is:
1 - most effective
2 - most frequently requested
then finally:
3 - potentially interesting for research.