What kind of screwdriver to open base of 2010 15" unibody?

It seems to be dependent on the screwdrivers... I bought a set of bits at fry's and the #00 was too small and I had to use the #0. They turned out to be pretty crappy quality, so I ordered the 54 bit set from ifixit, and the #00 fits perfectly. Just make sure that before you start using any pressure, the screwdriver is seated quite firmly into the screw without a lot of "wiggle". If its too small or large, you'll end up with a stripped screw.

In general though, if you have the time, I'd order the bit set from here since overall they were much higher quality than anything I had a available locally. Only took about 3 days for me to get them as well :)