I think a metal one would be easiest, because it can be welded
Plastic welding?
Anyways, I think I am going to basically have a metal tank with a homemade auger welded into the side at an angle. The auger will come up fairly high off the ground. 6-8 feet? And then have a flexible tube come down to direct the feed.
If I do plastic, then I would like to use one of those liquid tanks that fit on a pallet, usually with a metal cage. And then have a PVC pipe auger off of that. It would be about 8-10 feet long perhaps. Anyways, can the PVC be plastic welded to the material on those tanks. I am not sure what it is called. If not, could a bracket be built for the auger?