"I am trying to find the line for premiums paid by self employed individuals. Ideally, I would like it on the "C", as he hasn't many deductions for "A"?"

Health insurance premiums for self employed are never a Sch C deduction, they are an adjustment to income on Sch 1, Part II of the 1040.

Im not familiar with ProConnect tax Online, but doesnt it have  Search box that can help you find the entry area for Self Employed Health Insurance?