For 2019, pre-tax contributions would be maximized by making the maximum permissible 401(k) regular elective deferral of $19,000 and catch-up elective deferral of $6,000 from your wages, reducing your W-2 box 1 amount to $25,000 and box 12 showing $25,000 with code D, the S corp making an employer contribution of $12,500 (that's 25% of $50,000) reducing the pass through income to $87,500, and, if your spouse is not covered by a workplace retirement plan and is under age 70½ in 2019, your spouse making the maximum $6,000 regular traditional IRA contribution plus $1,000 catch-up if age 50 or over in 2019.
It might also be possible to add a defined benefit plan that would reduce pass-through income and provide additional taxable income later in the form of a pension, but I'm not familiar with this.
Since the money put into these retirement plans and the earnings thereon will eventually be taxable (at the tax rate that applies to your ordinary income at the time of the distribution) , you might want to consider contributing some to after-tax Roth accounts instead, since distributions from Roth accounts, including earnings, will be eventually tax free. You might also want to consider paying the tax now and investing the money into investments where growth is taxed a long-term capital gains rates rather than gains being taxed as ordinary income when distributed from traditional retirement accounts.
