Use an accountant. At ten employees, the costs of a mistake can be enough to kill a company without a lot of money in the bank (and if the company has a lot of money in the bank then using accountants isn't a big deal). At ten employees, a company should probably have an ongoing relationships with an attorney and insurance agent.
The goal is to have systems where the right thing for the usual cases happens by default. Then the business can focus on business rather than administration. The "dumb tax" on tax issues can kill a business.
