I just wanted to make sure they were charged well enough without over doing it!
You are well advised to do so! Keep a close eye on Li-Ion's when charging them, pay attention to what TMG said, and you'll be OK. They shouldn't be charged, ideally, to over 4.20 Volts, 4.25 at the most. It's not good for the cells. If you go higher than 4.30 Volts or so, it can be dangerous.
I'm guessing your cells were probably not quite finished charging. I believe 4-5 hrs on a WF-139 is normal, I don't own one however.
As JBorneu, I think more or less alluded to, you could optionally use a better charger and cells. At the same time, a lot of people have success with them.
Dave
P.S. I like your avatar! My Aunt and Uncle were big MacGyver fans. They once told me how "brilliant" they thought he was. I looked at them and said, "Yeah, there aren't too many people than can take a box of toothpicks and a handfull of paper napkins, build a hang glider, and fly 4 people 3 miles to safety, from a second story window.......... in Kansas."