Originally Posted by Andy

I did that last year and I'm doing it again this year. I know I'm an outlier but I'm sure there are others who do the same. I'm trying to get a large annual RHA spillover.

I set my Fed exemptions to 10 and don't have state tax.

For my 3 Jan paycheck, I had:
Earnings: 7300.65
FICA/CA EE: 633.85
Pretax deductions: 41.80
After tax deductions: 208.88
Fed taxes: 0
Pretax 401K contribution: 6416.12

I do 100% pretax until I hit $24K, then do 100% post tax until I get close to $60K (2017) in my 401k, including company contributions.

I also converted all of my post tax contributions to Roth 401k so that the money grows tax free. It's a bit of a hassle to do with Schwab but I don't want to pay taxes in the future on gains that could be tax free with a simple conversion. Since the money I converted was post-tax, there is no additional taxes for conversion (other than taxes on gains prior to conversion).