First, you are doing this without the axle shaft or brakes installed right? If either of these are installed, that is most likely where you are feeling the resistance.

The hub seal can also create quite a bit of friction. If you didn't put a little lube on the shaft/seal lip, then that could be your problem.

It has been a while since I did this one, but no, I don't believe that you over tightened it. As long as you were following the steps and turning the hub while tightening to 60 lbs, then backed off 5-7 clicks, you should be fine. The hubs will not turn as nice and free as you would expect with new bearings because everything needs a little bit to seat itself. If you are still worried, the best thing to do is to keep an eye on it. Do this by putting everything back together (except for the lug nut cover/center cap). Drive around the block listening and feeling for anything out of the ordinary > touch the hub (the black part protruding from the wheel) - You should still be able to hold onto it with no problem > If OK > Drive a few miles at a higher speed > Stop and touch the hub again (it may be uncomfortable to touch, but it still shouldn't burn you) - The bearings will heat up a little more than normal until break-in is done. A better way of doing this is with an infrared thermometer (but I don't have one, so the old fashioned way does the trick) - If using a thermometer, 200 - 250 is about the hottest you want it to get, Over 300F and there is definitely something wrong.

During the first few miles, make sure that you take some turns left and right. Doing so allows the gear oil to flow to the wheel bearings, which will make sure that they aren't running dry (which would not be good).

Did you pack the bearings with grease? If so, this can cause it to feel tight.
Did you lube the bearing before install? If so, good.

It is better to be too tight, then too loose...Giggity (Family Guy Reference)...you will just wear the bearing a little faster and create a little more heat. If it is too loose, then the bearing can move around and will fail much much sooner (and your seals will wear and leak quickly).

So, if you can still turn it by hand, it isn't extremely tight.
If you have vertical movement in the hub, then it is too loose.
If you can turn it by hand, and you have no vertical movement, then you shouldn't worry (I wouldn't).

I hope this helps. I have installed a lot of these kinds of bearings in the manufacturing world, and just kind of do it by feel (since I usually don't have any specs).

If everything checks out fine, but you are still worried, spin them by hand after you have put on 50 - 100 Miles. They will feel just like they should.