misterbonkers, I think the current standard roster is along the lines of
8 on - 5 off - 6 on - 2 off
There are exceptions of course.
As for paying for the IR, yes when there is no one left on the market with an IR then they will pay for them, taking the most experienced pilots first. I've seen the database of prospective pilots and there are a lot on it with an IR already, plus all the type ratings you could want.