Threadless flat backs as lobe piercing jewelry?recommendations for 14k gold and lab diamond options?

Hey all, I’ve always had trouble wearing jewelry in my 2 lobe piercings on each ear because I have really thick ear lobes (lol) and regular butterfly back earring posts are never long enough and pinch me. I’m thinking getting some cheap 8&10mm threadless flatback posts to see which fits better and taking it from there. I don’t have so much experience buying body jewelry because I only have my lobes and septum w a horseshoe I never change. If I buy 14k gold 18g threadless flatback posts in a length that’s comfortable for me would any of the threadless pushpin charms for the front from any brand be compatible with them?? Do the charms have to be made for a specific gauge and length? Or are they all interchangeable? I also do have a preference for 14k gold and lab diamond jewelry if anyone has any recommendations for body jewelry websites that sell jewelry in those types of materials straight to the customer?