If safety (including yours) is a concern, then someone should mention a few things...bungees snapping, and falling off the trailer has been mentioned. But the single most dangerous aspect when I was pulling a flat was those damned V-boards! They are most dangerous on a load that requires tarping as well. And on what I used to call a Pyramid load. That's where you have it on the trailer with it 2 skids wide on the bottom, and one skid centered on top. From the back it looks like your hauling a pyramid. Dont remember how many times a V-board came skittering down the tarp to clip me in the nogin while I was trying to tighten the straps over it.
My advise is to go van, but if you want to do flatbed, just be constantly aware of your surroundings, and listen to other flat drivers. Yes, many are brash, many are over-eager to give an opinion, but many have some good ideas to make things easier. And they are eager to help. One of the unwritten rules of flatbedding is to always help the driver in front of you fold his tarps, while he is being unloaded. Not just as a courtesy, but it will get you unloaded faster as well...good luck
Flat bedding is for the young IMO. At my age I'm quite happy to pull a Van. I just close the doors, and I'm off....