Let the club do all the leg work and keep a bit extra for themselves. This will save you some time consuming effort and provide some stability. Gyms almost always have more and better resources than individuals. Hold an amazing class and let them promote it for you. A great product always reaps rewards… when properly advertised.
I think the first answer, “the club to get you more clients and thus keep large % as commission”. If the club is willing to promote you and provide your clientele’ that sounds like a “win-win” situation however, not knowing the percentages, this would ultimately free up some of your time and money spent to self promote.
Wichin You Great Success!