Getting back <gasp!> to Mark C's (the OP) original question ...

I'm in exactly the same boat as you, sir; an infrequent kilt wearer. Our mainstream Lutheran church does a full-on Christmas Eve service -- candlelight, organ, choirs, the works. Like your congre, our attendees tend to spiff out their dress a bit. Several years ago I decided to try my kilt for the evening, with coat and tie etc. Heads turned but I got nothing but fine comments and compliments. Both pastors loved it. One year when my wife was very ill I skipped the kilt for Christmas and had everybody asking where it was.

I highly recommend you choose the kilt for church. You won't regret it.