MBS is adjustable. Use as little as you wish up to the maximum. I normally recommend leaving the main bang as that shows the radar is working during calm days when you might not have any other targets at open sea. Your raw main bang isn't changing. The suppression just covers it up so you don't have to look at it. Main bang is the radar firing and hearing itself fire then the returns. If yours is exceptionally large then it most likely isn't mainbang but reflected RF from nearby items on the boat. You might try using sector blanking for those objects to cut down on reflected signals. Main bang is normal for any radar and how big is relative so not sure if yours is really all main bang (normal) or you have some reflections going on the boat. The suppression can make it look pretty for those who don't like to see it but most radar guys want to see MainBang.