Should I create a simultaneous Part-time Sole Proprietorship and Part-time single-member S-Corporation?

Question

I am self-employed and my business has two distinct parts:

1. Engineering and Design - which makes $50k income / year
2. Manufacturing and Sales - which makes $150k income / year

I am currently running both of these lumped together as a sole proprietorship, doing business under my name. I spend approximately 25 hours per week in each of these, for a total of 50 hours per week.

However, I am considering splitting these two into the following:

1. Engineering and Design -- as a sole proprietorship (or single member LLC)
2. Manufacturing and Sales -- as an S Corporation (single share holder)

The advantages I see here are numerous:

1. Although 100% of my income from #1 would be subject to SE (self-employment) taxes, only my salary would be subject to SE taxes in #2.
2. Since I am spending half my time in #1, and half my time in #2, the reasonable salary for #2 for a full-time salaried employee is 100k, however, since I am half-time, my reasonable salary is $50k. Therefore, $100k would be paid to me as distributions, avoiding some SE taxes.
3. My wife helps me with #1, and I would hire her as a W2 employee under #1, allowing me to also offer her a Section 105 Plan, which would cover her family's (i.e. her and me) health insurance premiums and health expenses, as a deductible business expense. I do not have this benefit under an S-Corporation.

Any thoughts or feedback on this approach? Any other recommendations?

Basically, my goal is:

1. Minimize my tax liability (especially when it comes to SE taxes), while still being under the "reasonable salary" range.
2. Maximize business deductions, such as health insurance premiums and medical expenses, etc, which both reduces SE taxes as well as reduces the total taxable profit.

How can I best meet these two goals? Is my approach a good one?