Hi, I’ve worked with similar situations before – bike bar-grips. First I’d suggest you aim for no post-mold machining. That’s a big expense and it should be possible to design the need out. Second the linearity and concentricity issues. Are there any alignment features on the Aluminum pole? I presume it’s extruded and then machined, so you could punch a notch into the end of the aluminum as an alignment and anti-rotation feature.

You could overmold the grip in place. Some punched holes in the pole would make great keys to lock the grip and deal with your ‘tightness’ issue fully.