athwartship fiddles don't need to be very high, 3/4"-1" works fine. There is not much force from pitching or gravity working to pitch the counter top contents off the counter. If these fiddles are too high, it can be a PITA to use a knife or other utensils even with a cutting board raising the work surface up. The fore and aft fiddles should be high as practicable to counteract the heel of the boat. 4" plus works very well. Did 6" on my last boat but you have to be careful. An errant pot broke the first one. The second one lasted for years but probably we were more careful with what we put on the counter.