I believe there has to be some taper, somewhere. You will never get a perfect fit with a parallel tube and socket - there will always be a little movement. The grating noises are very disconcerting, with an alloy tube in an alloy socket, and I needed to pour in some polyurethane, when I used this system on my mizzen mast. Then I couldn't get the mast out again, and had to cut it off. The stub is still there, under the cabin sole.
If you don't want to use wedges, you could try a tapered wooden plug in the end of the tube. This need not have a round end, but could be square, or otherwise shaped to resist rotation.