Goose,
In your case, if my memory serves me well, you could run a ¾ hp electric motor (15 amp circuit) with a 14 ga cord from your garage to your wood pile. If not a 12 ga would be more than enough.
On the supersplit, you might want to check out this thread.
https://www.hearth.com/talk/threads/7639/
On the safety side, a careful, safety conscious person would be OK with it. Those “accident prone” people should not use it. Also the one I reviewed recently had poor shielding of the flywheels and mechanical components to a point where it was relatively easy to get a hand, finger or clothing in the works. Finally there were a lot of kick outs from wood that was not straight or was cut out of square. The latter two issues could be addressed by a small redesign I believe however the speed issue (2-3 sec cycle max) is likely not addressable.
Many rental guys will not rent these machines because they are too fast for safety. In fact one of the rental guys near me actually has one as his personal splitter and likes it a lot but he will not have them in his rental store.
Don’t get me wrong, I do like the machine and if I had not made mine I likely would have bought one. It just needs a bit of fine tuning like most machinery.