Go to a website called contractpilot.com (or something like that). Thats probably your best bet unless you know a number of operators and can work through them exclusively.
Everyone I know that does contract is paid on a daily basis plus expenses. I've never heard of a contract pilot getting per diem. I've seen light jet contract rates from $300-500/day. I've also seen super-midsized as low as $400/day. Whatever the market will pay.
I know a few that make a decent living doing contract. Some even have it worked out to where their recurrents are paid for, but those can be rare. You'll have to figure everything into your pricing; ie. recurrent training, insurance, retirement, taxes. If you figure a one time recurrent a year on something like a C560 can run around $9000 a year, how many trips are you going to fly in order to pay for that, plus make a living?
Food for thought. Good luck with your search!
Regards,
2000Flyer