"learn to play the instrument properly"
There are certainly ways of playing that avoid buttons sinking into holes, but isn't it worth noting that more sophisticated instruments don't have this problem in the first place?

As for fitting a coupler to cut out one bank of reeds, in theory this is possible, and they do work the way Manitas describes, but in an instrument that wasn't designed that way in the first place it would require major skill and surgery to fit, and frankly it would be easier to retune the reeds to dry tuning (2 ranks at identical pitch) if that's the sound you want. Or shell out for an instrument that has a coupler if you want to switch sounds. The cheapest practical option may be to buy a second instrument (second hand perhaps) tape over 1 bank of reeds in one and leave the other in standard tremolo tuning.

Anahata