A few points in various posts that warrant a closer inspection. Rather than repeat them allby quoting, I will refer to the post number. It is 98 in the shade with a hot wind blowing and the only outside jobs I have are all in the sun, so I am hiding.
Millwood#11. I have had another look at the YouTube video. That digger is carrying a lot of soil (and haulms) along with the potatoes and this prevents the damage that would otherwise occur as mentioned by Millwood at #13 with thin skinned potatoes. At #16 CliffordK asks how much abuse potatoes will take. The answer is very little. They suffer internal bruising very easily as well as external wounds – a fact that most people I have known fail to realise. They are not quite as fragile as eggs, but various fungal problems are likely to occur in bulk storage. I used to produce Certified Seed grade at one time as well as having a large number of direct sales outlets for ware, and quality was always the way to sell potatoes.
Muddstopper #18 says the ½” rods will be at 2” centres. That leaves a lot space for good sized seed potatoes to fall through. Volunteer plants will be a great problem the following year. Also, I am not keen on bare metal rods because there will be some damage. The spacing and metal size is not a problem though. Lengths of plastic tubing can be fitted over the rods, a lengthwise knife split allows for easy on/off, and a ½” internal diameter tube will provide the necessary protection. If there are numerous smaller potatoes then another tube to fit over the first reduces the gap even further. I use this system to make bearings on some pieces of equipment. Cheap and easily replaceable. The tubing can be removed for rock picking, or left on if going for smaller sizes after the bigger ones have been removed.
CliffordK #22. I too have always used hills as you call them – ridges or drills where I originated, but it is common practice in many countries for smaller scale growers to grow on the flat, particularly in mainland Europe. As CliffordK says, hills mean that your furrow bottom is below the level of all potatoes, so harvesting is so much simpler, and needs a lot less power than digging deep into the ground.
Millwood #15. When you said 200K tons, meaning 200,000 tons of rock, I assumed you were joking, but meant you had a big problem with a lot of rocks. Most rocks of the world weigh in at about 2 tons to the cubic yard, so 200K tons is roughly 100,000 cubic yards. I though I had done well in removing about 4K cubic yards in a couple of years. 3 mixed with soil to fill in an old shallow quarry (now overplanted with olives) and the rest to make new farm roads.