Looks like I lost both crank dust caps on my first ride.

I'm currently trying to tweak my front derailleur. After tightening the front derailleur cable (there was a lot of slack), I noticed I have to turn the friction shifter all the way to the bottom to move the chain to the larger gear. Is that normal behavior? Also, after setting the low and high limits, on the smaller front gear for example, I get chain rub against the front derailleur cage when the back gears are set to either the smallest or largest cog. Is this normal on the Nano? I just read on sheldonbrown.com, that if there is chain rub, I can "trim" the front derailleur with the non-indexed shifter, but should I even need to do that? Can the chain rub be adjusted out? I don't believe I've run into this before on other bikes.