I used the curved basing pins, and they are around one inch long...just measured one. I also have some straight ones, and I like the curved ones better.
I also use a tool that sort of looks like a screwdriver to help close and open the pens when they are in the quilt. It is called a Kwik Klip. You might be interested in one of those if you decide pens is the way you prefer to baste. I've never tried any other method, as this works fine for me. The Kwik Klip keeps my fingers from getting sore and speeds things up. You put all the pins in, leaving them open, and then take the Kwik Klip and just snap each closed.
http://www.google.com/#q=Kwik+Klip&t...52096839510432
Dina