OK If I were you I would check out the Style Threads:

http://www.xmarksthescot.com/forum/a...ement.php?f=98

I would go for the Black Stewart, but then again I just got a Black Stewart so I may be biased just a wee bit.

As it is Semi Formal I would stay away from the PC as it is a Formal Jacket. If I were you I would look into an Argyle Jacket instead, they can be dressed up to formal standards or Semi Formal depending on the accessories you pair them up with and are therefore more versatile than a Prince Charlie.
Please stay away from a suit jacket, the cut does not look right with a kilt, suit jackets are too long too loose and they do not have a proper front to accommodate a sporran.

SWK shipping is notoriously fast so I do not think you will have as problem there.