That's why Gus makes the big dough!:notworthyI would build a plywood box with 10' sheet goods that the column could slip into.
The top of the box tack a fence for your skill saw so the cut is down the middle.
Get the idea yet?
Cut, rotate, cut.
Obviously you need to register the column correctly both times but I'm sure you can handle that.
I might not cut all the way through both ends so the column keeps shape and finish it off with a hand saw after both cuts are made.
I hope this helps