Is someone going to pay to advertise for pilots? Surely, all you need to do is put a post on pprune and you'll get swamped with replies.
As for contracts, if you want the right people rather than bums on seats, you'll have to be paying a rate than enables a captain to earn a minimum of £90k (more for other parts of Europe) and F/O's 1/2 to 2/3rds of that, depending on experience. If a short term contract, you'll have to pay in excess for £120k. How you split pay between hours, blocks, standby's and so on depends on the operation. You'll also pay for type rating, recurrent checks and training, uniform, car parking, any positioning from base and when away from base, all overnight accommodation (in a four star hotel). You'll also provide a company phone. In return for that you should be able to cherry-pick your candidates. As for hours, use CAP 371 as to the absolute maximum.