Bill, I should be thanking you. Then again you kept those cinnamon rolls all to yourself.
Dexter recommends a 10 down if possible, the brackets you have now look higher than Dexters high lift.
I believe the "side mount hangers" are the "extra special" bolt on bracket, also called the AP mount or ...
Any shop worth their salt will want to see and measure yours before ordering. If they order based on your specs and it does not fit, it is your responsibility.
Things happen. Paul Neumeister that does a lot of axles on bolers up here, has his numbers down pat, yet had a few axles for the same trailer come in that were off a year or so ago. Whether that was a supplier problem or build problem or labelling problem, who knows? But the axles had to be reordered.
Get a good grasp on the charts in the Dexter specs as to ride height and angles. Go out and measure yours a few times and compare them.
The diagrams and ordering chart here might help you see things from a different perspective.
and there is some more info here
Trailer Axles Torflex and Spring
I recall we had to do a little adaptation to get the Dexter to fit on my Trillium
4500. If we wanted to keep the front to rear orientation of the spindle in the exact same position we had to notch the frame a bit or shorten the brackets. I think the brackets were about 1/4" or so longer. So learn your bracket dimensions.
Look at your pictures P1010059.JPG and P1010060.JPG, that is where we had the problem. The extra thickness of the bolt on brackets made it a little more difficult to fix the problem. We were able to easily work around it.
You might want to measure that on yours and compare it to Dexters specs.