The OS #8 is considered a long plug, and will work just fine in your engine.

I wouldn't consider the OS plug "industry standard" at all. It's a very common plug (and very expensive), but it's actually shorter than "standard" long plugs, so if anything it's an industry-non-standard .

I've never seen this be a problem, however. And I have seen an engine that had more-than-normal compression run better with the shorter plug. It's not unlike the old trick of putting two washers under a long plug.

Short plugs have a shorter threaded section. They are usually used in small engines that have a thin head, where a long plug would actually stick down in to the combustion chamber and cause problems. Unless you fly engines in the .15 and smaller range, you'll probibly never need one. (and most all the .15's I've seen use long plugs).