It is so very frustrating that most contracting companies try to sell this 6 on, 2 off rubish especially when it is for long haul operations. With clever rostering you could easily get maximum hours from pilots with 3 on and 2 off. With slightly less hours and less salary you could offer 2 on, 2 off or 3 on, 3 off and have no problem finding crews.
6 on, 2 off is only for crew with no family or who want to escape their family or who are desperate to find a job. There simply are not that many experienced, qualified crew who fall into that category around anymore.
If they want to entice good pilots from good jobs they need to get a lot smarter and offer reasonable conditions!