Any reason you dont want to drill bigger holes? Is it because you want to keep the CP as it was originally made or maybe you dont want to risk messing it up if you dont feel up to the job?
It looks to me like the top of the control panel screws off. I would suggest making a new panel with propper buttons to replace it. That way it will be easier to make from scratch rather than trying to open the original holes out, and you will also be preserving the original CP and you will always be able to put it back.