Never had 7 bells meals whilst deep sea, I remember as 3/m doing 0800 -1200 then straight to the saloon and back on the bridge from 1230 - 1300 so 2/m could have his lunch, as 2/m was called to relieve 3/m from 0830 - 0900, and 1/m from 1800 -1830, as 1/m never relieved anyone, on some ships as 3/m relieved 1/m from 1830 to 1900
Always had 7 bell meals on coasters when working 4/4 or 5/5 or 6/6 my preferred was 5/5 as gave you a different time on watch every day, hard but happy days (most of the time!), of course there were crap times, but without crap times you wouldn't recognise the good times; but all in all would do it again in those times, no electronic aids, just your sextant and a magnetic compass and an occasional D/F Bearing, if sparks was any good, not forgetting the beer bottle binoculars and the telescope resting on the wind breaks, but we still got there.