MoR nailed the issue I was having: the length of the vest in question. So the I and the other groomsman will forego such, and use belt: I've got a couple we can use.

We've already done a "dry run" with the plaid: works fine as a basic shawl.

The whole idea here was for the three of us (Best Man, Groomsman, Groom) to be similar, but NOT identical... with the groom "popping".

I'll post a pic or three from the wedding, once it's over. And tanks for the advice!