The nitrogen cycle time really varies. On my current 55g, I used the same canister filter, plants and some of the gravel but it still took 12 weeks to cycle. I would say 4-6 minium. There's chemical that claim to eliminate the cycle process but to be honest, I think they slowed it down when I tried them. Patience is the key. Put a small amount of flakes in the tank every other day and that will give the bacteria something to feed on and move the cycle along.
As far as water changes, I used the bucket method for the longest time. I then broke down and bought a Python. OMG what a difference!!!! Just attached it to the faucet and go. I will suggest it to everyone. It's really not expensive and well worth it. Yes, 1/3 is the way to go but it's so easy with a Python.
"Cycling best friend is a good liquid regeant test kit, and a good barber to fix your hair after you pulled half of it out."