Larry
"Uncle Larry"
I tested hitting something that will produce a higher pitch and it definitely registers well past 400. It just feels like the reso is so dang tight already I'm nervous continue cranking down to get close to 350.
You have to get past that nervous feeling. Just keep going till you hit 400 and you'll know see for yourself how much tension they can take. The 3 mil snare side film stretches quite a bit.