Hey Eden
I think once things get to be about a 1/2″ out of level, then you might want to consider using a floor leveler or make an adjustment with framing (leveler is usually easier, especially if you don’t plan to replace subflooring)
A 1/4″ will not be noticeable, and you could technically level it out with additional thinset on the low side (if using large format tile)
thanks
steve
