Arisaka T99 Huber Trigger install problem

Anyone with experience on where and how to lighten up and tune an Arisaka T99 Trigger? The Huber concepts trigger doesn't work as there isn't enough engagement.

So, I cleaned and polished up the bearing surfaces on the top of the original trigger, and under the sear flat on the bottom where it cams, and lightly polished the sear contact surfaces. Trigger is stiff on first stage, then horribly heavy before breaking. I'd guess 15lbs plus. I've tried different Bolts and 2 other firing pins from my other rifles, and to no avail.

I was going to drill through and tap the front portion of the trigger for a hex screw, as with the huber, to allow for take up adjustment of the sear.

Anybody with suggestions other than "you're investing too much time with something that would be better as a wall hanger, and spend my time bidding and buying a better Arisaka T99"

Have you stoned and polished the engagement notch on the cocking piece? I'd try that next.

I have replace the coil spring on the front of the sear with a lighter spring and the trigger was a lot better. Stone the engaging surfaces first. Caution: Don't go too light or you may have an un-safe trigger. Keep your old spring.