Never used the red wasp but just ordered 3 due to this thread.
I'm going to be ordering some this week myself because of this thread.
As far as the question which call if only one, I guess it would be any mouth call. A sudden and close second, and would be number one except for handling it is my box call. I had never used one before about 5 years ago when I got one at my FIL garage sale. He had simply found it in the garage when he bought the house, he's a non hunter. I grabbed it, learned how to call a bit with it even though I hated box calls, and took it with me that spring. I was on a bird who wouldn't budge from his bench or his ladies and I could move, so in desperation I took this gangly thing out and managed to make a hen turkey sound with it. He hammered right back, so I hit him again and he hammered again! I said huh? In about 20 seconds he gobbles again but he had closer half the distance already and was pretty much in range. I put the call down and it squeaked and he gobbled at that too! He pops up over the rise and boom he's dead. That was the only bird I had killed between 2017 and 2021 because of the decline in birds. I used it last year on the two times I hunted and called both birds into range but missed one of them.
I hated box calls. Hated them I say! And I never would have spent a dime on one. But I will say this…the only time I've been fooled by another hunters calling is when they use a box call. They are very "henny" sounding to me