"IMO, this comes down to what position is your client comfortable taking"

The self-employed plan doesn't have to be in the name of the business; the IRS clarified this one long ago. To give parity to self-employed sole proprietor, it can be in the name of the individual, or even their 27 year-old child's or spouse's coverage, as long as they are not eligible for an employer's coverage.

Another detail to consider is that the $3,000 exclusion is an election. I would consider whether you don't want to elect into the exclusion. Also, multiple Sched C cannot be aggregated, nor can the insurance premium be split across them. Lots of details to consider.