muzzy has by far the best and simplest way of locking the blades down, on the 3 blade models, that I have seen. Most heads cut just 1 1/8 inch and print good groups (not all in the same spot but good tight groups when useing the same head) I use a variety of mechanicals my self. I have some 2" cut for the turkeys and a bunch of 1 1/4- 1 1/2 inch cut for deer/ and other 4 legged game. they all fly to the same point as my field points. they are really great about that. I do have a 100 grain 4 blade muzzy I carry with me and often shoot it at squirrels (little buggers deserve it, darn chater boxes).
I saw some nap thunder heads on sale once and gave them a try just because they were really cheap to buy and you got a lot of them. when assembeling them i found out the only place the blade accually gets locked down is on the notch in the very front base and rear base of the blade. that i did not like so I guess ill just give them to some one who likes thunderheads i guess.