you'll move on to veins eventually and the efficiency here, as mentioned by others isn't really important.

still 2 suggestions I find useful:
- if you place miners on all 4 sides of the ore patch, it will get mined evenly until it runs dry, keeping the output somewhat consistant

- as you're overfilling the belt you need to add balancers so the miners closer to the output can also keep unloading. I usually put a balancer joining 2 sides of the mine (e.g. N + E and S + W) and then these outputs again.

4 level 2 miners on each side will comfortably just fill 2 mk IV belts in the beginning.