Maybe too short
Jeff,
I just finished that step. With the pushtube cut to the length per the plans and the cones pushed in to where the taper meets the flat (the correct amount), the assembly is just barely long enough to screw the rod end bearings in the correct amount. You want to be sure to screw them in more than 1/2 way to ensure the assembly doesn't seperate if the jam nuts would become loose.
I would try to get those cones pulled back out. I screwed in the end bearings so I had more to grip on to to push them in. You might find something with the same thread that you can clamp in a vice in one end and screw into the cone on the other. That should give you the grab it takes to pull the cones back out.
You're right, if you prime the insides of the tubes first that makes the cones VERY tight. Course the instructions say to assemble the cones and pour primer into the tube after assembled and slosh it around. None the less, that's how I did mine too. (hope you made sure to prime the insides of the cones too before you pushed them in.
Having said all that, I really don't know how critical the bearing centers dimension is! It seems it will really only effect the vertical position of the stick when the elevators are neutral. Maybe a quarter or half an inch isn't an issue.
Good Luck