Jim
Not to put you the spot but, Gothot roasters have a cast iron end plates with cast iron spokes and carbon steel cold roll drum.
One of the current roaster in my shop for rebuild is a 120 kilo Gothot. When I get back to the shop Thursday i can take some photos if you all would like. Their is no Stainless Steel in the drum of this roaster. Also I believe that the drum gauge is about 12 gauge carbon steel. When we have had to replace a drum on these old roasters we have found that carbon steel cold roll is what the materials was used. This is the same materials we use on Probats, Gothots, JB perforated drum, Royal roasters perforated drum, Primo roasters,Perfekt and Diedrich are a few roasters that all used CARBON STEEL COLL ROLL DRUMS

Jim
It would be great to actually see a cast iron drum. Stainless steel well yes some of the roaster mfg are doing stainless steel, I personally do not see any advantage to using stainless steel. I have talked to them and no one has been able to prove it is better in fact from my personal experience they ten to help promote scorching and tipping. I believe this is in part because you can not get a stainless steel drum to season very well if at all. I have worked on those machines but normally the company's I play with has the same mind as I.

Ok hear is what I have noticed on the drum materails
Carbon steel - seasons well, has a much better heat distribution, you can run the drum at slower speeds if you want, you can get more convection if you want, I don't seem to get the metallic taste as often as I do with stainless steel, cost effective and don't wrap as fast if you have a power failure, you need to shut down a hot roaster and dissipates heat faster.

Stainless Steel - seems to tip and scorch easier, need to run high drum speeds to make work to over come uneven heat distribution, does not season well, cost a bunch, and wraps easily.

Now to help some of you out I work on mostly 5-120 kilo roasters and 99% high end specialty roasters. We also have designed our own sample roasters and again they use carbon steel drums.

Interesting, thanks for sharing Marty. Those Gothots look spectacular.

12 gauge is much thinner than I would have expected on a roaster that size. Is that typical? If so, do the burners heat the drum directly?

i can take some photos if you all would like

Yes please.