I bought the 2 1/4 length tapcons with a philips head. I didn't see ones with hex heads at home depot... Unless maybe i did... do they also have a straight head for a screwdriver on them?

Are the 2 1/4 tapcons too long for cinderblocks? What length do you guys normally use? I normally use #14 2 1/2 wood screws for regular stud installs, so I tried to pick out something similar for concrete, but I'm not sure if I need them that long. I don't want to drill through and hit a hollow spot. That may weaken the holding strength.