If you put some lighter gauge strings there will be less bowing from the neck which can cause some buzz, which may need some truss rod adjustment which seems to be tricky and a boring job on your guitar type... Also lighter strings gives a weaker tone.

Since you said your problem is higher strings at higher frets , I think we can assume it's a high action problem , this can be adjusted by lowering the bridge towards the guitar body taking care that there is no fret buzzing at any fret (specialy higher pitch ones).
This is a super easy job , but if the results didn't satisfy you or you couldn't get the action low enough without buzzing you'll need to do some work with the truss rod.