Let the cows calve in their existing environment. It save unsettling them.
Try to make a corner of the individual mothering-up pen into a sanctuary for the calf. Calves seem to be genetically programmed to seek a safe place to lie.
We have 10ft x 10ft pens. They mostly calf on slats then we move them to the pens. We have a calving gate in one of these and open up two pens usually to use it.
Do u find 10x10 is big enough?? Im thinking of making some same size out of cattle hurdles along feed barriers but worried if its big enough so that the cows wont lie on the calf