a few tips, use nitrogen to purge the lines, not compressed air
Make sure the dryer is the LAST thing you install and preferably purging with nitrogen as you do once you remove the caps or just do it really fast and pull a vacuum. there is a desiccant packet in the dryer filter and it must stay away from open air otherwise its trash. they are filled with nitrogen from the factory and why they have caps on them. reusing the old dryer is not worth it as it will not do didly squat.
Replace all your orings and dont trust the PAG oil level, purge all the lines and drain the compressor and fill with measured oil.
Weight in your charge, no additives, and make sure you purge your lines when charging or vac if you have a 4 port gauge manifold.
Happy to help but dont half ass it or you will be doing this again very soon.
it helps to charge with nitrogen to test for leaks too