My son's christening...

[English Bloke]

A fly plaid wouldn't work with the jacket I have (and you will have). You would really need an epaulet to thread it through to stop it falling off your shoulder and a simple modified suit jacket won't have one. As Chas also mentions, they are a fuss apparently and require constant adjustment and you have better things to worry about. I wouldn't if I were you. Go for comfortable not fussy.

Now that's out the way, I think Ron (Riverkilt) was referring to your mode of transportation rather than your attire.