Geez - you guys are a bunch of nervous nellies. A honda Civic would tow 3500lbs, no problem. That's hardly any weight at all.
Barrels of water? C'mon.
And he's hauling steel beams - which are simple because the weight is compact.
I haul stuff up to 10,000 pounds all the time on my trailers.
You need to be more concerned about getting it on the trailer, getting it off the trailer and making sure it's strapped tight in between.
A pair of straps will not be enough. For a load like that I would probably take about 8-10 straps. You can use your heavy straps over top of the load to make sure it doesn't bounce off, but you also need to make sure it can't shift side to side or forward and backward.
Assuming the lift has two main beams, I would put a couple heavy straps over top, then put a smaller strap - 1 1/2 inch from some point in the trailer to each end of each main tube so it can't shift fore and aft.
make sure you have enough extra straps to tie down any loose parts that might get blown off in the wind.
You can never have enough tie downs and straps - go buy a couple packages of 1 inch motorcycle straps as backup. I also carry a package of 48 inch heavy zip ties plus I have a coil of wire and my clamp-tite with me and those things have saved me a couple of times.
Several months ago I was hauling a forklift about 125 miles in the rain and I lost the seat bottom somewhere on the road - didn't think to strap it down.