I skipped the riser platform in my basement theater and I think risers are a waste of money
Three months ago I finished my 9x11 basement theater in Akron with a flat floor and staggered seating, and everyone on the forums told me I would regret not building a $300 riser. Last week four friends came over for a double feature and nobody in the back row complained once, mostly because I put the second row on cheap $40 bar stools I already owned. Why do people act like a riser is required when a $20 box of furniture pads and a taller stool fixes the whole sightline problem?
My riser was built by a guy who measured twice and still cut wrong, so you may have saved yourself more than money. Your bar stool setup sounds like it does the same job for a fraction of the cost. If it works for your room and your friends, that is really the only test that matters.