Hey Rob

I have several dress sporrans that you are more than welcome to borrow to use for the wedding. 10 bucks shipping is a lot cheaper than buying a new one of good quality, especially if you are already springing for a new kilt and likely a chunk of the wedding too as the father of the bride. As long as it is after noon or evening event, and you are wearing your PC I would go for the dress sporran over the semi dress.
I have a simple black leather hunting style with a chrome cantle, as well as several other chrome or chrome/enamel cantle fur dress sporrans I would be happy to send out on loan (it's not the first time for me doing it). PM me if interested and I can send some photos next weekend when I get home from a trip I am on right now.
Regarding the belt, one thing I have done on occasion was to wear a plain black belt with a dress coat but slid the buckle off to one side so that shiny bit does not poke out from under my waistcoat bottom, althought a little of the leather may show depending on you coat fit and level of activity. I used to do this when I was a bit heavier and needed to wear the belt to hold my sporran hangers I was using instead of a chain because of my ale-gut.

Jeff