Gas stick smootheness

I've got a "little" problem. The gas stick isn't moving equally smooth. At the bottom end, the resistance is high. When moving the stick up, resistance increases a little, then decreases to reach a minimum in the middle. It raises again when the stick is moved up from the middle. It's not much change, but it can be felt and it is disturbing a little bit. It seems, the plastic part the stick-break is gliding on, isn't in a perfect shape.
Is there a trick to make the stick move equally smooth and get a constant resistance, no matter of the stick position? Some TXs uses a sticky grease on these parts ... but I don't know if your plastics can take it.
Currently I would judge the feeling of the gas stick a bit below "ok". It's not living up to the quality of the used materials.

I can confirm the "unsmoothness" around the middle! And would therefore appreciate a solution as well.

Does it get better if you release the force of ratchet wheel and tighten the non-ratchet wheel?

Since I fly helicopters, I only use the non-ratchet wheel. I think this issue only appears with the non-ratched wheel.

Same on my TX at the low end it is harder to move the stick.

But during flight i do not notice it.

I have a new TX with the same question throttle stick set without ratchet and the stick tension is fine around the middle but seems to have a hard spot or rough spot at both top and bottom of travel

any thoughts would be appreciated

Thanks

Bernie