I would like to add to the undergarments (or lack thereof) advice: If you should decide to go commando, you might want to get another kilt (an inexpensive one, given that you're saving for the wedding) and get used to the feel of going around regimental for a while.

Otherwise, you'll be at your own wedding and feel like you're re-living that dream where you go to school naked and everyone's staring at you, even if you are perfectly covered.