I would definitely go for the tank and wear a more sedate collared shirt. (Red looks like a cardinal--the clergy, not the bird--and might be a bit overwhelming.) Ozman's attire shows a good choice, I think.

A plain collared shirt lets everyone knew who the clergyman in charge is, but it also doesn't "overdo." YOu can wear a tab collar like Ozman or get a full collar; both look good with a black or gray shirt, and the price won't break the bank. Of course, I don't know what denomination you come from, so that may influence your thinking as well.

I've never performed any sacerdotal duties while kilted myself, so I am a bit envious of your situation. Keep us posted, and let good taste prevail.