The 7424 and 7336SP are the same machine except that the 7424 comes with a 5oz counterweight for 5" backplates and a useless polishing pad instead of a 6oz counterweight and 6" sanding backplate and polishing pad for the 7336SP. Get the 7336SP if the prices are the same or cheaper, you are getting a better deal.
eshine sells LC pads and myself, but I don't carry any in stock, margins are too low.