No. Pretax come off Sched1 which reduces QBI, and thereby your QBI deduction. Post tax is not reported in your return, but is reported to the IRS by the custodian. What i have found helpful in reduceing self-employment tax is providing benefits to a employee-spouse. Employee benefits are a deductible business expense. Direct contributions to a HSA, QSEHRA reimbursements, heath care premiums, etc are tax free now and in the case of the HSA also later. Take those savings to offset the taxes on your post tax contributions. Having an employee means more paperwork, reporting and more work. But everyone needs an accountant, office manager, benefits manager, billing assistant and admin.

Just be aware that as a pass-thru entity, that pre-tax Solo 401k contribution might cost you. For every $1 you contributed, you likely loose $0.20 of your business QBI deduction, netting only a $0.80 tax savings today. But future you will be paying taxes on $1 when you withdraw that later. That means that future you will probably need to be in the 0-15% lowest brackets to make pre-tax contributions tax efficient today. This is a problem that W2 earners don't encounter. Looking back on things, past me should have switched to mega backdoor Roth's for my spouse and I in our last 5-10 peak W2 earning years. Now self employed, the Solo 401k was just going to make my tax situation worse. Of course everyone's situation is different and tax planning is an uncertainty itself.

Yes.

In the automation safety world, you are expected to account for "reasonably foreseeable misuse". The standards do not define that - the automation supplier and the equipment owner are required to perform their risk assessment to determine what possibilities and hazards are associated with that. It really boils down to - do you make it easier for the person to perform the task in the safest and most desired manner possible and enforce that with policies or engineering controls.

If it is trivial for someone to defeat the safeguards or if they have an incentive to do so (i.e. get to sleep an hour or read the paper on the way to work) and do not reasonably believe that they will be harmed in doing so, then you are not providing a safe system.

Does Tesla need to account for no driver in the front seat - unlikely as most reasonable people will not be sitting in the back seat.

Does Tesla need to account for a driver using a steering defeat device and not be paying attention - likely. These are readily available on Amazon, there has been ample proof that these types are devices are being used, and drivers have incentive to use them. Most reasonable people using one of these would not consider this "stepping in front of a train". In this case, Tesla's own marketing and public statements are working against them.

LPFM stations do interfere with signals of larger stations. A local high school station near my house - WPHS - is supposed to broadcast on 89.1FM.

However WPHS interferes with "large" FM 88.7 CIMX broadcasts in an ~ 2 mile radius from the location of WPHS. When tuned to 88.7 FM CIMX , the static and interference from WPHS makes it impossible to listen to CIMX in the area. The inference is not isolated to 88.7 FM but extends to adjacent channels 88.5 - 89.9 FM and can be clearly heard in this entire spectrum - so clear that you would assume that WPHS was actually broadcasting on every FM channel in this range.

WPHS http://www.wcs.k12.mi.us/cousino/WPHS%20radio/inde x.html

Coverage area.
http://www.radio-locator.com/cgi-bin/pat?call=WPHS &service=FM&status=L&hours=U