If the tank IS cycled you don't need to do a large water change. I do 25%-30% weekly gravel siphoning and water change, with any tank with a betta in it that is cycled and 5 or more gallons. Even if the bioload says I can do say...10%, I still do the 25%.
Everyone has their own way of cleaning their tank, but I've been told once to do 50%, but all other times 25-35%. So I stuck with 25% :)
Snails are not bad. Yes they can explode into millions
but only if they are given the chance! My males only ever tried eating snails, but they never liked th shell.. if I had too many I'd squish the snails and feed them to my males xD
Fasting is good one day of the week :) the reason people prefer pellets is it is easier to feed amounts (3 flakes vs. 3 similar sized pellets), pellets are better for them, and yes the flakes can get messy!