Only product I'd ever use would be BioSpira... Cycle and StressZyme aren't actual cycling products, even though they claim to be. The general consensus with them, I belive, is that they have some benefit AFTER your cycle has started. The bacteria in the bottles are in spores to protect them and prolong their life. Only outside reactions would make them break out of the spore (ie: ammonia, nitrosomas, etc.) and actually start to reproduce.
I like the natural way of cycling too. It may take slightly longer, but you know it's cycled and don't have to worry about it not being.
If you explain a little more about your tank situation and current water test readings, maybe that will help.