I have a DublDuck I keep locked in the safe under gaurd because it gets me every time, it's a 4/8 and I think that is what it is , but it only gets you if your applying pressure , a full hollow does flex , but in my opinion, it won't unless your pressing to much or angle is too steep, I never had trouble with the full hollows , I started with one and and that's what I learned how to use, now. Use 1/2 hollows mostly cause that's what most of the custom guys are doing because of wheel constraints or they don't want to go any deeper, but I like them! Tc