I guess I never thought about it, but some ideas come to mind.

Larger hole: One would need a reed with a wider head, or an oval opening so that it fits under the same reed. A tear drop shape reed would alow a larger opening.

A longer reed: I guess this would, in effect, be the same as what Crazy Herb says, but I gotta wonder.

One other thought: couldn't you put a small spacer between the limiter and the reed and get a little better result? This would also alow the reed to open more but would it cause other issues?

How about a thinner reed?

Tom