[ELZ's930]

If the clutch travel checks out then you may be dealing with the previous owners poor shifting habits. There should be no grinding. It sounds like you have figured out how to minimize the grinding but with proper shifting it should shift well.

The syncros are a weak point ( especially 2nd and 3rd as those are often "rushed" ) but some folks have managed to make them last for 100K miles.

I don't think the oil will make a difference but would be cheap enough to check.

Good Luck,
Leonard