You have to have some confidence in jacks and stands. What type of surface there used on will play a big part in how safe they are. I have no problems jacking and supporting the trailer. Or for that matter any other vehicle I have now or in the past. I use at least 1 item as in another jack or stand as backup. As anything jacked up, no one will be in in to cause movement and I do not get under anything that if the jacks/stands fail I will not be crushed. A simple piece of 2x4 or 2x6 will make a bigger foot print support when used correctly. Only remove and work on 1 wheel at a time. Bottom line if it seems too unsafe for you. Pay someone to do the work.
2013 24RKSWE (27ft TT) Cougar 1/2 ton series
2013 Ford F350 4x4 CC 6.7 engine, 8 ft bed 3.55 rear end lariat package
Retired from Oregon State Police in 2011 than worked another 9.5 years as a small town traffic cop:
As of 05-2020, I am all done with 39 years total police work. No more uniforms for me.