everyone has their way to do cycling of tanks, the basics are the same. the reason i do water changes or reccommend that water changes are done is for the following. first, to get a newbie in the habit of scheduling time for maintaining their tank(s). they can kind of get the feel for what is the best time for them to maintain their tank according to their schedule. also so they get the feel for the tank from the beginning.
second, water changes are required after the tank is set up to keep the levels down. doing small water changes after the ammonia has spiked will help to keep them down during the cycling so as to not overload the establishing biological filter. if small water changes are done during the cycling there is no need to do a large water change at the end of the cycle which can remove a large amount of the essential bacteria that you have established. imo, water changes over 75% are very risky.
as far as the ammonia goes, i would reccommend feeding an empty tank and letting the waste from the uneaten food create the bacteria. anything that you add to the tank that is not designed for aquarium use is a risk and should be dealt with very carefully. it seems like in the last few years though, using ammonia to cycle a tank is becoming more popular. all it does is shorten the time that it takes to cycle the tank by adding instant ammonia. beleive the saying, "good things come to those who wait" is valid here.
not trying to say anyone is right or wrong, these are the reasons that i do the things that i do. have set up quite a few tanks, not only for personal use but for others, including my daughter's school and have never had a problem with them. just passing along what i have learned.
maggie