i looked at a bunch on you tube, most were poorly made. there was one big one that the guy could swing 360 degrees around his shop to cover everything. i had an over arm on my table saw before and didn't like it. always in the way so it rarely got used. but YMMV !
working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.