That might be a possibility, just making the weapon end a bit "thinner", so the weapon would be smaller and lighter.
Maybe i could even go with less reduction then to speed that thing up a bit.
Have to do some drawings and calculate the new weight of a front end with that style and if that would help.
maybe get the weapon more to one side, so i could get the motor on the other side of it... well... long day(s) of scetching this will be.

Also good to know drums often use stationary axles, somehow that didn't get clear from most build diaries.

Somehow i am also thinking a bit more of a wide disc or short drum now, since a short beater wouldn't be much different from a bar with a long hole in it, and i'd think a more round shape could be more efficient, distributing the incoming forces better. but will have to see how the dimensions and the weight left look when i redesigned at least the front end.

Would it be a possible way to basically build two discs, also put the teeth into those, and just connect them with a (toothless) tube?
the middle part of that tube would only be for added stability and to get more weight from the inside to the outside of the weapon.