I also have two. One is growing wildly, and will make an awesome replacement heifer, the other is from a smaller framed angus based cow and he is ok.
BW's varied widely, from 60 pounds to 100 pounds. Not sure he will work on a wide varity of cows, but will serve the purpose on bigger cows needing some moderation and growth.
They're not supposed to look like Heat Waves. I know everytime I put a straw in a cow I made a little prayer for a heifer calf. That's not to say that I expect the bull calves to be throwaways, but I use him hoping for females.