If you are keeping it there, almost permanently, it makes no sense to lift it using the axles, most everyone complains about trailer bouncing, and this has a lot to do with the trailer sitting on springs or torsion axles.
Your best bet would be to buy 8 jack stands placing one on each corner and then one in front of and behind each axle to give you the greatest support.
I found these at Northern Tool for $22/pair, this would provide the support needed.