Arguments for the resistance of the pallet (the drums are another debate) I put a load of 200,000 N to see how the pallet of the First Stage reacts which will take the maximum deformation. I'll let you look. The shells are not subject to any notorious vibration so as long as you are far from the elastic limit time does not play (except corrosion of course).
I don't know what @ronathanwill say but as designed in the latest version you can put from 1 to 4 kegs.
Obviously, if there is an idiot at the end customer who does not put four drums in floors 0 and 1, this does not engage the responsibility of the pallet manufacturer.
But these considerations have long since exceeded, for this post, the normal (not to say simple) help provided by the forum. I helped@ronathanonly because it doesn't have SW simulation and since I was seeing stuff that was not going well at all I suggested other solutions.
Kind regards
PS: @Charles you were able to download the file you asked me for ;-)
Thank you for this 80*40*3 version, it suits me of course. Moreover, we will start with 4 prototypes of this type for full-scale testing. In your ASS there is only a row of 4 drums but their mass totals 8.4 T so the results are correct.