axle size - spring - other questions

[TacoTruck]

Been reading a while, but first time post... be gentle.

I am starting a project this fall. I have been napkin sketching ideas for a while now and what I came up with something of an abomination. Think of a 10' cargo trailer with inbound wheels and a 75% radiused rear wall. Dry, I am figuring about 800-1000lbs. Loaded, not likely anything over 1800lbs.

Through out out my planning I have crossed paths with several difficulties, but foremost is the suspension.

My plan is to have the right be about the same width of a light SUV tow vehicle, or around 70". So if I went a 48" frame/axle, plus building out to tire/wheel width, I would be left with something around 62-64". Now being a little thin in the trailer would not be of any issue to me. If I had to pick being wide or narrow, I would gladly take narrow.

Problem I have is that I want to run a drop axle and can not seem to find anything less than 5' AND 3000lbs capacity. As well, I want to run brakes, but I am running into the same limitations.

First Q - If buy a 60" (perch) axle and shorten it to around 52". No big deal right? This would solve my axle issue and I could make up a few inches over 48" to be more inline with the total width I am looking for. By my understanding I can shorten a straight (not cambered) axle. Even if it is a drop axle? My understanding the best practice here is to cradle the axle on an appropriate sized piece of 1/4" thick channel iron, scribe a straight flat line on the axle, cut the center out of the axle, sleeve the axle with a mending tube (with holes for rosette), line the scribe back up for placement... weld sleeve ends and rosettes. Sound reasonable?

Second Q - Springs. Is there any reason I couldn't go with 2000lb springs? My only concern is that when parked, if we get the whole family inside we will surely be over 2000lbs. Would this be okay? What if I ran jacks on the rear to take some weight?
See, I really don't want to go 3000/3500 pound springs, because I don't want the trailer bouncing around like a jackrabbit on meth, but don't want to create an issue either of having too low of a spring value either. Would the use of a simple "helper spring" be a reasonable option here? Do you think the difference between 2000lb springs and 35/3000 springs would matter that much?

And that's it for now. I'd appreciate any input you might have.

Thanks!

[KCStudly]

Something you need to consider is frame outside width vs hub face-to-hub face track width. There are design limitations on how far away the spring perch can be from the hub face. If you stick the hub out too far away from the spring perch it puts too much bending load on the axle.

Another thing to look out for on drop spindle axles is clearance between the drop leg and the outside of the frame. Don't assume that you can narrow it solely based on inside-to-inside of your tire side walls. The drop portion of the spindle may (probably will) stick in further than the tire side wall and will likely be above the bottom of the frame.