Yes the loading of a sheet film in an expert drum is very simple and reliable. Compared with a Jobo 2509N reel (6x 4x5") it's so much easier. Jobo is also recommending a pre-soak for C41 and E6 due to the tempering of the big drum itself.
I am sure that with these advices the result in E6 processing will be OK now. C41 and E6 are full standard processes so every deviation on this standard will lead to a worser result.
Sucess with your next development,

Robert