The cycle thing is a weird question with using pre-existing tank matter. With my 20 gallon I used about a bag of old eco-complete that was sitting in a bucket for who knows how long. I rinsed it very well and added a fresh new bag on top. I then added water from a 370 gallon system we have had going for gosh...i would say a decade. I put driftwood with java moss, some giant elodea from out of our pond and 1 amazon sword. I then dosed 5 ml trace, 5ml excel and 1 ml of flourish. The very next day I did a 5 gal water change and threw in a baby blue diamond discus, more elodea from pond, dosed ferts again and added diy co2. 4 days later did another 5 gal water change and tested water, .25 ammonia and .25 nitrite and nitrate was around 50 ppm, GH 14 and KH 3. The very next day I repeated with another 5 gal water change, and added 14 cardinals, 7 brown pencils and 3 undescribed specie of corydora. Added dwarf chain swords, and ozelot sword plant. Dosed all ferts again including some macros this time.
Needless to say, today is the 21st day my tank has been running and I have not lost one plant, fish, shrimp etc. Granted I have added a lot more plants in that time and went to a 50% WC weekly regime with dosing liquid ferts on Fridays and Mondays. My ammonia is 0, my nitrite is 0 my nitrates stay high between 20-50 ppm and my phosphates are over 3ppm (test kit doesn't read higher). I have not had any algae outbreaks either. Plants pearl up very nicely and they seem to be growing well. The old leaves have died off a bit on certain plant species from transport and replanting I presume, but there are many new leaves sprouting and I have had to trim the stem plants twice so far.
Which reminds me I need to test my water today. I don't know about most hobbyist, but I like to write everything down in notebooks that we do to the systems. Not to mention it's cool to look back and see what you had 10 years ago. Or when a fish dies, to look up how long you had it from when you first purchased it.
Thats my experience on fast cycling.