Ask HN: Transparency with compensation and salaries

Any HR professionals here willing to talk generally about compensation packages and total employee cost to a firm? Reading here http://www.kalzumeus.com/2012/01/23/salary-negotiation/ mentioned that an employee cost (payroll taxes and benefits etc.) could equate to 200% of stated gross salary. I'd just like to know a bit more of how the process works ok the buyer side (the employer) so that I -- the seller -- (my skills, time, blood and sweat) can be rightfully compensated. Some context: back end data engineer transitioning up the stack to data architect with 3 to 5 years experience at a firm that is publicly traded with a market cap just under 1B.