In NSW the contracts are usually 'exchanged' after the finance has been organized. Essentially the contract doesn't get signed by either party until everything is unconditional. As a result, there's no need for a finance clause, or any other clause. You've got 2 weeks to get everything lined up. If something doesn't work out, you never enter into a contract.
As the others have said. Get to know how people do it locally and see if it works for you. Again you do things on your terms because your the one buying it!