Tim,
You need to take some solvent and remove that paint from the ways. put the solvent on a rag, do not pour it on the ways, if Required you may need to use some 000 steel wool. The rest of that stuff should clean up with WD40....
I believe I would make a power Z add-on a priority investment; otherwise your going to have one arm larger than the other....
I have oilers and I still brush it on....
Have you greased the Z Axis lead screw? Sticks is correct, if the gib is loose it'll bind, and I can see by your video it is loose... Get some 2x material.... 2x6's.... set them on edge on the table and set the head down on them so they support its weight. Make certain the Z axis locks are loose (completely disengaged) then snug the gib into its slot further by tightening the screw. You cannot adjust the gib with the head's weight on it, it has a lot of leverage on the Z Axis carriage when it is suspended. I use grease on the lead screw, run the head all the way up, remove the Z Axis accordion cover and put grease on the screw from just under the head down 6 or 8 inches then run the head to the bottom and back up, it'll help your issue.