I think you may have the wrong idea about early weaned calves nutrition.
Protein is important- but you are still low Need to start at 18% and drop back to 16% after they are on feed real good.
At that size you almost need sBM to supply the protein or you cannot get the energy high enough.
You need to be thinking about keeping the hay down to 10-25% of their diet.
tubs are generally useless at that size.
Calves that size need to be on about the same energy as a finishing ration with higher protein.
Get some 450- 500 lbs calves - they are alot easier to feed and start. And can be done with what you have in mind.