more likely it's crud on the caliper pins keeping them in contact. Air in the lines would mean less brake pressure, not more. Pull the calipers apart and re-grease the pins they slide on.
Depending on the corrosion issues in your area, might be the brake pistons dragging.
I still have my standard calipers sitting in a box. Pay the shipping and they are yours, if they can be of use to you. My Sub was hecho in Mehico and has lived all its life in SoCal, so zero corrosion issues.
Question as well on the H2 springs, did you ever see anything if they are same ratign as original z71 components. I need to change mine finally / in the next couple months, might be doing a lot of towing and all I'm finding right now are Moog 81069 HD or maybe some Delco Pro HD variables for about the same ~$60 price. Want to get them ordered very soon.