Once you go rogue and start trampling forage, it is very hard to stop, because you get more grass every year. Damm stuff will not stop growing. That's why I am trying RR soybeans. Even then you have to spray 2 or 3 times to be able to see the beans.
I used to specialize in < 350#, sometimes going down to 250#. That kind are not mature enough to grow well on a high percentage of perennial pasture roughage. Rye grass or wheat are different. So you need to yard them till they get closer to 500#, or grain them heavily while they nibble on grass. ADG is a key to profit.
A lower risk start up approach would be to pick up a couple light calves that match some of yours, mass medicate with the good stuff, and bucket feed them in a lot.