Does anyone have experience with sizing and pattern matching for stair runners? We're getting a custom stair runner installed that has a large diamond pattern on it (it's got vines going back and forth in a criss-cross). We thought we were set on the sizing, but the person doing the binding is making us rethink it.

Basically, the design consultant from the carpet store recommended that the runner start 3 1/2 inches in from the edges of the stairs. We really like this width. She said nothing about pattern matching, and we didn't know anything about it to ask. So we ordered the carpet.

A couple days ago the person who is going to be binding the edges came out to take final measurements. He said that because the pattern is basically a 12" wide (a full diamond), he would make the runner 24" wide so that we have 2 complete patterns running down the stairs. But this makes the runner 5" from the stair edge (and even more on part of our stairs where the banister is). On our particular staircase, I'm concerned that 5" in from the edges is going to make the runner seem way too skinny.

I'd really like to keep the 3 1/2" from the edge of the stairs. But will it look bad if we have the two full diamond patterns PLUS a little extra on each side? (I am terrible at visualizing this sort of thing)

Or should we go with the binder's advice and have a skinnier runner with supposedly better pattern matching? (He does this all the time and seemed to really know what he was talking about)

Maybe it's my fault for not doing my research, but isn't this something that should have been brought up to us when the carpet store came out to give an estimate and design consultation?

Sorry this was so lengthy. Kind of hard to explain in a post.

Any advice is appreciated!