@JoeVade
I am only familiar with employer sponsored 401(k) plans, and to the best of my knowledge, you can’t make after-tax contributions to a pre-tax 401(k), and you can’t make any contributions to the 401(k) except through payroll deductions.
If you are referring to a strategy involving making after-tax contributions to a solo self-employed 401(k), you will have to discuss that with someone who has more expertise in that area.
