Re weight rating, I found a thread where Gringeltaube had given the (M105) part numbers of the bearings as 39590 and 39591 so I looked them up for their weight ratings. Timken gives a rating based on 90 million revolutions and a rating based on 1 million. The 39590 and 39591 have the same 90m rating at 9730# but they are different at the 1 million rating. The 39590 is rated at 37,500# and the 39591 is rated at 65,300#. Together (each side), the bearings are rated over 19,000# for 90 million rev and someplace around 100,000# for a 1 million rating. Talk about overbuilt!
Then I went to the tires. The rating on the side of my 9.00 NDCC said 3,750 each (duel) or about 7500# together. The weight rating on the side of the (A3) 14.5 says 7100#. Thus a duel 9.00 is slightly higher rated than the single 14.5.
I don't know if the D200 has the same bearings, hub and axle dia., but I bet they do, thus similar ratings.
Mike has plans for his M200 axles, and I don't really have funds to purchase others, so option 4 is off the table for me. I have to work with what I have. And at this point, I have to say the 9.00 duels shown above are not road worthy. They are on for moving around the farm and came off my boomtruck when it got new shoes (from 3 M105's), badly checked (but still holding air). Thus my availability on hand does not include (
9.00's.... but I do have 4 ready to go 14.5's on rims and several spare tires good enough for a trailer.