ok I need some help with getting my 06 trailblazer ac working

things I have tested so far and their results:

• fuses are good
• ac relay 44 is good (swapped it with brights to test it)
• jumping ac relay 44:
  • ac clutch activated
  • pump spins without any observable noises (only spun 2-4 revolutions at idle)
  • during the 2-4 revolutions I noticed AC pressure sensor V reading on my bosch prograde scan tool went from 0.27V to somewhere between 0.33V-0.38V. Not sure exactly where it ended up as i did not keep the relay jumpered for more than 2-4 pump rotations
  • unsure if the AC relay command switched from "off" to anything else as i only had a glance at the scanner hence not remembering exactly what the peak AC pressure sensor voltage was
  • AC request stayed set to "no"
• jumping pressure sensor on dehydrator canister switches AC request from no to yes but does not start the compressor reguardless of if the ac button is pressed
• turning on and off the ac button and fiddling with other settings on the digital hvac dash module did nothing to get AC working and didn't change anything on the readout on the scanner only noticeable change was a snowflake on the digital hvac screen
• cursory check for leaks but found none
• tested grounds around the vehicle and found grounding points to be satisfactory also tested if there was too much voltage overwhelming a particular ground and did not find anything significant

planning on doing:

• finding my AC gauges and a vac pump and checking pressure
• more in depth check for leaks

things I would like to know

• what pressure should the system be when it is not engaged at 5000 feet between 80-90F
• what kind of refrigerant does it take and how much?
• when it is refilled what should the cold and hot side pressures be while running?
• is there something im missing and should check for this truck?
• what pin on the digital hvac dash module seds the ac signal to the ecu? I am guessing its a data stream from B11 so not just a pull to ground or a dc 3V 5V 12V or car power (12-14.5V) signal? can a tech 2 knockoff scanner tell if this signal is getting to the ecu?
• what does the ecu look for before turning on the AC compressor?
• what other things do I need to test?
• what do you think might be the problem?

about the vehicle:

• 2006 chevy trailblazer, i6, automatic, swb, with 150,000 miles on the clock
• bought it from a friend who stopped driving it due to syspension bushings being worn out and causing alignment issues
• it was sitting with periodic drives around the block and starts up to temp but unsure how often
• the exhaust cam has trouble adjusting after the oil heats up. I am hoping this is the valve being clogged or getting stuck and not the vvt oil chamber on the front of the cam. cant remember if it gets stuck sitting advanced or retarded when rpms are low. at higher rpms it does sortof keep up with what the computer asks when engine oil is warm. it has no problems keeping page with what the ecu asks when the engine is cold
• one of the front dome lights will sometimes stay on very faintly even with the key out after the diming happens
• the windsheild wipers and washer and rear wiper will often turnon by themselves reguardless of what you do with the wiper controls on the stalk and will not turn off easily. currently the wipers and washers fuses and relay is removed from the fuse boxes
• it has an aftermarket stereo system but the head unit is currently removed and the amp cap and subwoofer are disconnected from positive but still connected to ground
• heater works
• recirculation works
• unsure if blender doors move off of heater when selecting normal fan mode or ac mode it all comes out hot mostly due to arizona sun beating down on it
• defrost and footwell baffles work but baffle that sends air to dash vents does not move and dash vents are permanently stuck. I have the vent servo which i stuck in a safe place and now I need it since the dash is pulled apart for the ac repair and also the head unit swap but it is still in a safe place somewhere. also ac was working when my friend owned it and he had purchased the servo but never installed it so kept ac running through floor and defrost vents
• friend who drove it never raced or drove aggressively and was good with getting maintinence done as needed
• one of the speakers makes a hissing sound when the truck is off even with the key out but unsure if it still does this now that the head unit is out. it was very quiet.

Any and all info suggestions and help is appreciated! Thank you in advance!