At home on my concrete pad I use two floor jacks to raise on side of the trailer till the tires clear. All my trailers are std leaf spring suspension. Torsion axle have a lot of travel before the tires clear so be aware.
On the road I have a old 12 ton shorty hyd bottle jack that slides under my trailers axle tube next to the U bolt or the U bolt itself. Lifting one end of a 6k axle is only lifting 2500-3000 lbs which doesn't stress anything.
What ever method you use make a trial run at home. Some folks that bit into the trailer aid thing/ramp found it wouldn't lift the other axle while sitting on the side of the road.