I am replacing an faucet in my kitchen corian sink. The old faucet had a
single hole that everything went though; the new one has three holes. So I
need two new holes.

Is a hole saw the proper tool? A spade bit doesn't seem right. Any tips
would be much appreciated.

BTW; the old faucet is about 6 years old. The rubber gasket basically
disintigrated, so now it just flops around and can't be tightened up.
Replacing the faucet is just as easy as replacing the gasket, so I would
like one that doesn't have this problem.
So... Is this an inherent problem with one hole faucets, or was mine
poorly installed?

Thanks.