I know exactly what you are talking about and trying to do. I have an Anschutz smallbore target rifle with their 2 stage trigger. Anschutz triggers can be adjusted in any number of ways, including 1st and 2nd stage weights, 1st travel, and 2nd stage sear engagement. But they were designed with those adjustments in mind.
Unfortunately, what you have was not really meant to be so adjustable. The best advice you have been given is to call John Holliger of White Oak Precision and explain what you want. he will be able to tell you if it is possible or not.
BTW, my Anschutz trigger is set to 3 oz on the first stage and .5 oz on the second. It is, however, extremely crisp and controllable and completely safe. They are an engineering marvel.