You should've joined Virgin Blue.
No seniority, and with a points based bidding system 85% of crew requests are met every month.
You get 1000 points to spend every month, so if what you want is super important, you can spend the whole 1000 on it. Or you can spend varying amounts depending on the importance to you. This is also backed up with a standing 'lifestyle' bid eg max overnights, day trips, weekends etc, which costs no points as it is a standing bid. Points override standing bids.
It's a fantastic system, I almost always get what I bid for.