Paw pads tend to be much thicker than ears, so I would think the larger gauge lancet would work better. 25-28 gauge. Usually labeled for alternate site testing.
Have you adjusted the depth setting on your lancing pen? They usually have 5 settings and you'll need to adjust to see which one works best for your situation.
If you are free-handing the lancet, go in at a 45 degree angle, bevel up on the lancet. It makes it easier to poke if the bevel is up, but darn that tiny shiny spot is hard to see for aging eyes. ohmygod_smile