Dont worry about gas filling. Do following
- Hook both High and Low side Gauges.
- Get pressure pictures on low side and high side on idle.
- Raise the RPM to 1500 and then take pictures.
NOTE: While doing you need to
1. put your blower to MAX
2. Temperature to MAX Cool
3. Open Windows or Even doors
This will ensure max load on AC
Keep in mind if you want perfection here in Pakistan you better start DIY stuff or learn info and force mechanic to work according to specs, otherwise change your level of satisfaction......