Until the NSRA changed the rules, LSR triggers had to be 500 grams or more. I modified my S410 and a FX to reach 500 grams on the first stage alone, with just another few grams tipping the second stage. In other words the sear engagement was set very fine so the actual let off was still crisp.
The S410 needed a much stronger spring in the usual place at the front of the trigger guard, and the FX needed a new spring behind the trigger blade as outlined above.
The same technique should be OK to reach 2kg pull.
Last year the NSRA changed the rules to admit any trigger weight that the Range Officer deemed safe.