If you have a ranch you can make a new leaf with the size orfice you want.
If you have a regular mini you can try this, (now don't blame me if it gets messed up, as this is an idea, not something I've done, but something I'd do if it were mine.) Measure the orfice with a drill bit, get a smaller drill bit that you would like for the orfice to be. Clean the orfice with alcohol, dry, then apply JB weld to fill the hole. Let dry over night, then sand down where its pretty, drill out the orfice with the smaller drill, check it out to see if its suits ya. If not do it again till it does. Now take a can of flat black spray paint, Now don't spray it on moma's table cloth!
GO OUT SIDE to do it.! Touch it up with the flat black paint. Your good to go. 
If you have a regular mini you can try this, (now don't blame me if it gets messed up, as this is an idea, not something I've done, but something I'd do if it were mine.) Measure the orfice with a drill bit, get a smaller drill bit that you would like for the orfice to be. Clean the orfice with alcohol, dry, then apply JB weld to fill the hole. Let dry over night, then sand down where its pretty, drill out the orfice with the smaller drill, check it out to see if its suits ya. If not do it again till it does. Now take a can of flat black spray paint, Now don't spray it on moma's table cloth!