Officiating a wedding...?

[Randy McIntosh]

If the boots end up looking a bit much, try covering them with gaiters such a worn by the military and pipe band members.

Christoph

Sorry IMHO that is even worse.....

Gaiters (what you are talking about are called spats) are not meant to cover boots.
They are meant to cover the shoe to keep muck from getting into the top of the shoe and going inside.

This is not worn with the PC., stick with plain black shoes if that is all you have, leave boots and spats to a non formal look.