as far as makers, i suggest looking at the sales forums here and seeing what used straps others are selling. people here tend to own so many and rotate so often that i've picked up a lot of almost new pieces for less than original cost. use that to try out some of the makers that way you can see what you like and then order something totally custom. there are a bunch of aftermarket strap makers who make wonderful pieces and they can guide you through sizing and what will work best.
also if you see a pic posted with one that you like, email the poster and they'll be happy to send maker info.
it's sorta frowned upon here to discuss the maker/model in the open as it may be shilling or product placement.
i prefer my straps a little longer, 24/24 - so you'll need a larger buckle than what the watch comes with - aftermarket buckles are available cheap too.
Mike...NYC. My collection so far is a 312 and some cool straps.