Look for something like "12mm Rigid Flange Shaft Coupling" on amazon. They're a bit small but work fine. the platters i made out of 1/2 inch mdf, but about half of the disc I thinned out to 1/4 inch to keep the mass down (probably wasn't necessary).
I used wickets bent from coat hangers back - so long ago might be forward when lol. The main element these things reveal is the width of the ball. You may find shooting past obstacles becomes less stressful.
