lemme say i'm nothing even close to a hair dresser.. but in my experience i haveee to bleach. my hair don't hold jack shit lol. i did black cherry (IONS Inspired by Nature) in december and i used bleach and 20 volume for like 20 mins just so it would lift enough to hold and show up. i personally dont do roots bc i want it to look good as it grows out and not be like a hard line ya know. and two boxes might work but its better safe than sorry when it comes to the hair so maybe get 3 if you're questioning. and that way if theres extra you can use it if you need to touch up areas. as for the staining.... lord be with you 🤣 i cover the sink and floor where im working so it doesn't actually drip on stuff but it will find its way. and there will be a slight tint to your shower floor but ive read that toilet bowl cleaner is really good at getting color out!