On my radar for heifers is GLS Declaration (
http://www.selectsiresbeef.com/index.php/bull-database-view-page?bid=428&breed=Simmental), and I have actually bred a few heifers to him for fall 18 calving, and will use him on some spring heifers when we breed those.
I like his pedigree, and his numbers look good for us. I know he is not proven, but I know my heifers and what they can do and I think he is a good match for some of them, especially the ones with white.
Another one I use on heifers is HPF Optimizer. His calves flat out grow, and I have not touched a calf yet sired by him (at birth). He is not sleep at night calving ease, but if your heifers can handle high 70 to low 80 birth weights he is one to consider. He tends to throw some white, so I would not use him heifers with a lot of white. We have a heifer in production sired by him, out of a heifer herself. She is raising a dandy of a calf (sired by Elevate), has plenty of milk and keeping in great flesh herself. She is bred back herself for her second calf, and we backed her up 30 days.