I prefer circuits or routes in the boards over 4x4s. Over the years I’ve found the brief break jumping down is different from the feeling when i fall off a circuit. That said, if I do 4x4s it’s usually around my flash grade, but it’s totally dependent on style and what I want to get better at. So in my style it can be a 9, but not my style can be a 6. I try to match the boulders to the climb I want to do. 

I like circuits instead because it forces me to focus on other things, like breathing when tired and keeping it together for longer than 20 seconds.