Here is another take on what you are trying to do. For years we tried to breed some of our cows to meet the demand of the current market. What I found was that some of them were excellent mothers and had no issues calving. I suggest saving up and investing in some embryo's. Put those embryo's in those cows that may not be ideal but are good momma cows. Good recieps run 1000-2000 so those momma cows have value.
I-80 does not have a calf on the ground yet. He would be a gamble on how he might breed. I would take each cow and evaluate her back ground and genetics. Then look at your options for bulls. It may take a few bulls to accomplish what you want. In some cases I have seen Dr. Who with the right combo add some bone and muscle with the right cows. Direct Hit can add bone and muscle but may bring you down a tick on frame score, he won't add any frame. He will make a square clubbier type calf. On the higher percentage angus I don't think you can go wrong with Irish WHiskey. IW makes some awful nice replacement females with that cross.I have been wathcing Mercede Benz as he has a crop or two on the ground. They are looking pretty good. paddy o'malley may also work but my paddy females haven't had wonderful milk. Open Bar has seen some success. For us Ali was never consistent enough, he wasn't a "cow changer". I think he might be a good option for some of your better cows just lacking some of what you want. I am not a maine person but keep a few in the barn. I am surprised Knabe hasn't jumped on this one.
You have a who host of clubby bulls if you aren't set on higher percent maine. Like Vet Tech has suggested you can never go wrong with Who Made Who unless the cows have structure issues. Then steer clear of that cross. I had never used WMW for a calving ease sire but took a stab at it last year. Was VERY pleased with what we got on first calf heifer. Not saying he will always breed that consistnet being a 4 way plus cross.
Enough rambling.....
