Acceptable logging of HM FM 100k 200k

[pes949]

I have completed a HM this season and plan to do a FM in a couple of weeks. The question is what is considered acceptable for completing the piece in terms of rest periods? I was able to do the HM straight through in about an hour and 45 minutes. However the notion of sitting on the erg for almost 4 hours without getting up for a minute or two to stretch or to take care of bodily functions will be rough at best. Then to think of 100k or 200k that could be all day.
So how does it work if you need a break during a longer piece and still consider the piece valid for rankings in the Logbook?

[Citroen]

The PM3/PM4/PM5 will stay awake and running for 4 minutes when in "Rowing" mode. It stays awake for 2 mins in "Menu" mode.

If you press the [CHANGE DISPLAY] or [CHANGE UNITS] buttons that resets the four minute timer.

[Dangerscouse]

As long as you complete it and it's verified i.e. don't use 'Just Row' it doesn't really matter how many breaks you take as they all add to your end time. If you take longer than four mins you can ask someone to press the display button on the monitor to keep it going for longer, just don't press Menu!!!

BTW, 200k isn't a ranked distance; it jumps to 24hrs from 100km.