Regardless of the speakers used I recommend spacing them no more than about 10 feet from each other. The environment is noisy and you’ll have a tug of war between listeners close to a speaker claiming “too loud” while others will claim “can’t hear the music”. Ten foot spacing virtually eliminates this tug. Another approach would be to provide music only in the folding area — again with a 10ft rule. 

Consider hiring a pro and install a “70V system”. If the pro you contact does not understand 70V, this is not the person you should hire. It takes extra effort, but you can incorporate SONOS into a 70V system.  If I was on site, you might be able to talk me out of a 70V system, but you’d need to be very persuasive and endure my strong pushback.