Currently, none of the cordless impact wrenches will allow you to adjust the torque to those exact settings. (An air impact wrench won’t either for that matter.) The only solution is an attachment that fits onto to the end of the impact and then the socket fits onto it. Basically it is another “socket” that won’t let the tool torque anymore than the ft/lbs you set it for. However, these are very expensive little things. They are around $300 to $400. They are really made for production and assembly lines where exact torque is very important. The torque ranges you are describing are not that large and I think the torque attachment is overkill for you. Are you concerned about damaging the brackets and are you doing a lot of them? I would not be that concerned about 32 ft/lbs or 85 ft/lbs. The difference is not that much. I would recommend the Ingersoll Rand 3/8” cordless impact wrench. This tool is made from the same components that Ingersoll Rand uses in their air impact wrenches. I have personally used the ½” model and I was surprised at how well it worked. You can control it to an extent by not squeezing the trigger all the way down. If you barely depress the trigger the cordless impact will turn slower with lower torque. It is not “exact”, but you won’t shear the bolt either. (If that is your concern.)