Gasket go to Lowes or Builder square , I think they are call a plumers washer ( back rubber , (they don't seem to break down from the gas). For some type of fixture. But any how 1 5/8 " or there abouts. Measure you bowl OD and get the right one, you will need to trim the inside. It cuts easy enough.
I should have a latch around if you need one( e-mail me). Normaly I get a small bolt and tap the nut to the next size, cut a grove in the bolt and bend it around the wire of the latch. But thats on working tractors not a show piece.
Have a Good One !!