Stability is what Carl Strohmeyer recommends, and he's a professional aquarist with a lot on the line.
From the research I've done lately, it seems Safestart and other live (must refrigerate) products work better for a fishless cycle with it's high ammonia.
For help with a fish-n cycle, Stability, Cycle and others (room temperature) seem to be best.
Two or three weeks is a little optimistic but, if you're cycling fish-in, you'll be doing the required water changes anyway, and eventually your tank will be cycled.
and be sure you have a liquid teat kit and know how to use it.
What pH problems are you having?