In my experience, I have found that if you use fully cured LR (a decent amount...not just a piece or two) when you start up your system, the cycle will be pretty much non-existent. We had fish in our 29 within a few days (after the sand settled) after we tested the water...no problem.
I recently finished my 125, which took all of the rock from my 55 as well as about 30 more pounds (120 or so pounds). Fish were in the tank within a week (aquascaping held me up a little). Basically, if you start with established stuff, you should be fine. Still, to err on the side of caution, test your water a couple times just to make sure.