My Trip Lengths:
1 day
2 day
etc....
.....
all the way to about 19 days on in a row.
Then 28, 31, 32 days on in a row.

There is a minimum of 5? days off in between trips, if you want it.
My shortest block of days off (I waive the 5? day min) has been 2 days. My longest days off block was about 30 days off.

2 senior guys I met had 2014 all of Jul/Aug off....60 days in a row, basically.

In JFK 747 the "normal" trip lengths are 6-16 days on.