Opinions differ on cycling, and I'm not too strong in the cycling area. I was lucky enough to "inherit" a tank that had been running for 10 years, so there was no cycling. From what I could tell, and what I would do if I did have to cycle a tank, would be to buy 4 cardinals for it. Watch the water parameters, wait for the ammonia spike and the subsequent bacteria bloom, and BAM!--cycled tank. Then I would add a few more fish every week until my population is where I want it.
Opinions also differ on the hardiness of cardinals. I find they are very hardy, I have been slowly adjusting the water parameters in the tank with no loss. Plus a lot of people say to use something like zebra danios or such, but I've always wondered--what do you do with them after the tank is cycled? I for one don't like them.