Layering works! I haven't ever personally used the fert tabs, so I can't really say whether they would be good or not.
I do weekly 25%-ish water changes. I'll probably knock them down to 10% weekly changes, but I've had a little bit of a BGA problem, so I've been doing larger changes to help remedy that. The amount of water you change every week is really dependent upon your individual tank: most people are good with a 10% change, but if you have a high fish load, low filter turnover, low plant load, etc, you might want to change more water just to keep the water quality higher.
"How can you have any pudding if you don't eat your meat?"