Our push buttons have been sourced with hula hoops in mind. We have the lowest-mass, most-ideal push buttons for Polypro & HDPE hoop connections. These are smaller than many of the big bulky, obtrusive push-buttons that some hoop makers use. Typically used in conjunction with rivets.
Use a standard 7/32" drill bit ...Or for the most-precise fit possible, use a "Wire Gauge 9 size" bit, available at mcmaster.com ( product ID 28765A59 )