My bad, I forgot to mention the waistcoat. I will be wearing a light grey (i.e. very close to dove grey) vest.
Have you thought about taking the groomsmans glenplaid for yourself and swapping the shep check with him? It's your wedding remember and if you paid for them I doubt he'd have an issue with that. The other one will still look fine but a glen plaid would be a nice match to the trousers.
Not a bad idea. I know that he prefers the glen plaid over the shepherd's check, but I know that he wouldn't object if I asked.
Thanks for the input. If I have some time this weekend, I'll try to take a photo to post.