Chaps
The 18-30hr rest was an extract from UK CAP371 and aimed at UK airlines operating UK-Florida-UK day/night rotations. Likewise Airlines also ignored it. It could be argued that it was aimed at switching from nights to lates to earlies or vv but that was a consequence of the limitations of CAP371 not sensible rostering.
There is an argument that 18-30 night / day rotations are more manageable as highlighted by Sloopy Joe's earlier post. No one doubt's the Night rotation is tough but the day rotation allows Pilots to commence the recovery in the Companies time rather than there own.
The current plight for you Pilots (either of high or low morale) is that a lot of airlines are using the Boeing Alertness Model to check roster fatigue levels. It's well known that this is a "one size fits all" application and not airline specific. Each airline as we know is individually different in many ways. The other issue is Crewing Staff (love them or hate them) are now moving towards "I.T. systems Officers" where black is black and white is white and there is no grey (or perhaps even Red, Green or Orange if its a yes or a no)
You only have to look at Middle Eastern Airlines now - most require University degree's to get into the job, someone with a degree in common sense or a University of Life has no chance (I appreciate this might be Government driven also)
That might have been a rant, I should have been a Pilot.....