It is obvious from your photo that if the center disc were as they are in this photo, they were already flipped to cup outward. Most tractors are installed with the cup in and the tire installed as you now have yours depicted. THis is why most folks have to flip the center disc rather than remove the outside hub.
Trying to get that bolt back in the rim from the inside and put an nut on by yourself must have been a real bear, I know it was on my LS front tires when I had to swap the rim lugs from outside to inside and it was only loaded with air.
I just removed and replaced both tires on my Kubota B26 this morning looking at the hydraulic relief valve and strainer. It took about 2 minutes to remove the lug bolts using my Harbor Freight 3/4" impact, pull the tire, then 5 minutes of looking at the PRV and determining that I couldnt work on it with what I had then not more than 5 minutes to reposition and mount the tire. It is only a 12.4x16 R4 and not loaded but I didnt lift it, just rolled it and raised or lowered the tractor as needed to get the bolts aligned, tightened the nuts which snugged and centered the other lug bolts. Then tightened them with the impact and all done. Of course having the backhoe stabilizers made quick work of lifting and lowering.