RE: M_Boats: 12-28 fasteners?

Hi guys. I'm mounting larger halyard cleats on our M15's mast and I bought a 4 inch Schaefer jam cleat that uses a #12 fastener. 12-24s are easy to find. Now, 12-28s are an entirely different story. I'd like to use the fine thread to get a better purchase for the fastener. Anybody encountered an outfit that carries this rare size? Or am I overdoing it. Will the 12-24 work okay? Thanks. t Tom Smith & Jane Van Winkle Sandpoint, Idaho M15-345, Chukar M17-064, Unnamed