Start by a thorough polishing of all internal contacting metal parts. Use a high quality fine metal polish, a terry cloth rag, and Q-Tips. If you're good with, and careful with, a Dremel with its soft felt polishing wheel, you can use that as well. Do a detailed strip of the gun in order to polish all of the parts.
If necessary in your opinion, replace the connector with a lighter unit. Just make sure you get one made for the model 43. Ghost has connectors for the model 43. Their Edge connector gets good reviews.
Install a competition trigger spring to further reduce pull weight. I like the Wolf competition spring from GlockParts.com. This mod, in concert with the lighter connector, should get your 43 pull weight down to somewhere between 5 to 5 1/2 pounds.
Hope this helps.