Hence why you need to have a pressure check done...a 250 gallon tote of water is going to be right around 2100 lbs and this is well below your LA1150 or LA1153 loader spec even at full lift height and breakout force is even much greater...Not sure how my box blind thread has gotten to this point. My loader has no issues picking up a box blind, that was just a general statement about the loader. My loader is maxed out picking up a 250 gallon tote full of water from the back of my truck. I had to drag my no till JD 71 planter off a trailer because my loader wouldn't lift it and the planter was put on the trailer by a 40 HP JD tractor.
My L3830 can lift and carry a 250 gallon tote of water with a LA723 loader so there is no wonder the 40 HP JD lifted the JD planter...
Nothing personal and I hope this helps you get it lined out because it is leaving a lot on the table...Kubota dealership can do a pressure check and can increase loader pressure with shims which will increase the loaders capability.
To get back to the boxblind build I really like it. Since I have increased our south plot size to 2.2 acres I am looking into doing a blind build in the not too distant future. I like your design and I would make the floor square as you suggested. 12 feet would be more than plenty tall where I want to place it...