Here are the Paramours I did with one stock and one mirror chassis. The chassis tops were sanded and hand polished. Again showing what is possible from the kit.
If punching through the top proves to be a tough task, another option might be to drill a hole just under size in the side of the cabinet. Then thread the pot into the cabinet and add some short jumpers. A small screw driver could make the adjustment through the side while the amp sits upright.
No I did not remove the frames. They were polished as fully assembled units. I start first by sanding them with some 320 grit to remove the finish and then some 400 grit to smooth it out. Some light finishing with 1000 grit made the final polishing easier. I cheated on these a little by using some white tripoli and a 6" cotton wheel on my bench grinder to polish. I finished with some hand polishing with Happich Semichrome metal polish and a soft towel. Not a quick task but easy enough. It only takes time and patience.