A few trigger options for the 1600 series actions would be the original adjustable triggers (reportedly made by timney, I believe they are marked Tradewinds) if you can find one (they utilize the original safety tab), a standard timney for the 98 actions and Huber concepts trigger. I personally really like the actions, with another trigger in them!
The 1640 I'm currently shooting in 7X57AI is what they called the Deluxe model. It has a moderate MC comb and an adjustable trigger. I can't find a thing I dislike about the rifle, save for the kitchen-table stock refinish it had when I found it.
I sure wish Karnis were feeling well. He would do right by it.
