yeah, for me the smaller inner diameter is no biggy since i have a dremel with a cone shaped stone, so i can actually make an absolute perfect fit which will give me a better seal if anything. But ide be carefully with the drill. From personal experience, whenever i tried to enlarge a hole it always ended up shifting from the center. And it might also be really hard to hold the desk, the drill will probably grab it really hard. good luck.

and i said it too. its a shocker that these shims arent sold separately since it seems that they are a part that wears out all the time and quite quickly for that matter. After just 2 gallons of use when i took the diff apart, the shims had already bent and had grooves in them. One of my shims now was sliced in 2, lol.