The u-joint is just as collapsible as he pot coupling. Which is to say it isn't. The collapsability in the later columns came from the fact that the lower section slides into the upper section as you found out. Also the special square plastic washers holding the column to the dash allow it to break away.
Yes, you need to cut the "T" pin section off the lower column rod. Also, if you go with the u-joint it should be secured onto the lower column section with a couple beefy tack welds when you get it where you want it.
