Just a note that it seems there are 2 different people offering these gaskets.
Anyway, I have a set thanks to McMinn, and my original Lycoming gaskets with 120 hours on them were sealing well. That said, all six of the hold down flanges were anything but flat. I spent a lot of time with them with a piece of sandpaper on a sheet of glass getting them flat. Keep in mind, this is a factory NEW engine. The tube ends generally cleaned up with just a light pass on the same sandpaper, which is a good thing considering there's not much material to start with.
Yes, the silicone gaskets should fare better at overcoming this gross irregularity than the paper, but the silicone is actually more critical in the sense that it needs to be uniformly compressed, otherwise you will get significant "squeeze out" at the fastener ears.
Initial lessons learned (applicable across the board, regardless of gasket material): Make sure you have flat, true flanges, and make SURE the tube is seated in the recess of the hold down flange.