Jeremy,
I use those type rods a lot. If you put more line on them than the rod is long, it's very difficult to maneuver the fish on it and into the boat, without hand pulling the line.
I always tie my line to the rod and measure to the end and cut my line there.
Also, they suggest you don't tie the line just to the eye at the end of the pole, it puts too much stress on that little eye if you get a fish of any size.
As far as fishing shallower than the line you have on the rod, I use a bobber then. If you don't want to use a bobber, you can always twirl the line around the end of the pole until you have the right amount of line hanging down.
They have really given me a lot of pleasure catching fish, and are inexpensive too!
Good luck!
"Be Ye Fishers of Men" You catch them- He will clean them