My thoughts:
A firearms instructor providing instruction for licensing requirements is not in it to make money. They are in it to provide safe, effective instruction on the use and safety of firearms, and instruction concerning the applicable laws for their students.
If 16 hours is too much for you to do, then don't do it. If you truly want to help those interested in acquiring their licensing requirements to purchase their right to carry back from the state, then this so-called "issue" of 16 hours should not bother you. It could be done many ways... 4-4 hour time frames (personally I wouldn't want to come four times)... 2-8 hour time frames (one Saturday for two weekends, or a Sat and Sun of the same weekend).
Personally, if I were instructing the class, I would do two 8-hour Saturdays. Depending on what IL would require you to teach would, of course, depends how your curriculum would be set up. It seems to me the first 8 hours could be law, safety, types of firearms, etc. and the second Saturday could deal with actual firearms, teach safety and do range time.
From your original thread... $600 is absolutely ridiculous unless you were providing some type of tactical firearms instruction on top of the 16 hour requirement. To me, it shows the wrong motivation for getting into the instructing business, that is, if your instruction is only to help those get their licensing requirements. You talked of renting commercial space. Why? A lot of instructors will meet at a sportsmen's club that they belong too and will give them tables and chairs and a room. I knew of one instructor who taught in the furnished basement of his house. You are going to want to make this instruction feasible for the masses.