Can you or should you use an Electric Cement Mixer to prepare larger quantities of self leveling cement?
I would be pretty apprehensive of doing that. The working time of SLC is usually pretty rapid, often under 20 minutes.
With such a short working time, for the quantity using a big mixer, it'll be very challenging to mix, pour, and clean up in that short time window.
If you have a decent team of reliable helpers you could probably pull it off, just be sure everyone knows their role before you start mixing.