On 4/11 four steers we raised and are personally feeding weighed from 450 to 520. Those are on the small side of ideal weights for Houston (1350 full target) based on their breeding and projected weight curves based on their genetics and how we feed. We sold some others that are maybe 100 lbs heavier than that.
For right now, I'd say if you have calves over 700 lbs you'll be having to hold them. In my opinion, anything under 450 right now you will be better off shooting to stay a lightweight - you might could get heavier but wouldn't be ready "maturity" wise.