Of course, the size of the runway, weight of plane, and air traffic depends, but I usually never use my reverse thrust at 100%, especially with the auto brake enabled. What would be the perfect reverse rate?
It seems the comments generally do not go above 80%. Pretty good margin
Between 20-80% depending on how long the runway is, and how late I land. If it’s a big RWY like JFK and if I land in the touchdown zone (which I do rarely because it’s hard lol!) then I’ll probably do around 20% and slowly go up to around 40%, if I don’t need to stop quickly. If I landed a little bit past, I’d use like 40% then go up to like 60%. It all really depends though.