The Osprey will out mine it, so the first barge you will go for will be the Retriever
The Barge Way - Before we go any further, you must know that Buy Runescap the Procurer sucks. The Osprey will out mine it, so the first barge you will go for will be the Retriever.
The Retriever - A big advantage of the retriever is that it uses strip miners, which means a longer cycle (less dragging) and is MUCH cheaper than a battleship.
Skills you will need: Mining Barge 3, Industry 5, Astrogeology 5
I will assume here you trained Mining Barge to level 4 (3% bonus to yield per level) even though you only need level 3 to fly the retriever, as every little bits help. I'll also assume you trained Astrogeology to level 5, since it'll be required for the Covetor!
While we're at it, since you're serious about mining, you will also have invested the time in training Mining to level 5 as well.
Let's see what kind of yield a retriever can fetch with 1x MLU (on a side note, no mining barge, not even a covetor, can fit more than 1x MLU, no matter what skills you train.
As I mentioned, Mining Upgrades 1 will suffice for barges): 540 * 1.25 * 1.25 * 1.12 * 1.05 = 992.25 m3/cycle
Using Omber, this means 992.25 /0.6 = 1653.75 = 1653 units of Omber/cycle (per strip)
