Recommendation needed. Road trip break down. AC repair Florida panhandle.

[Deshet]

In a pinch I have purged most of the air from a system with a quick burst of 134a. Then roughly filled it by weight. That will get you ~80% performance. Auto stores will have loaner gauge sets and vacuum pumps for a better job sometimes. With Rapid refrigerant loss (oil everywhere) you may need to add a few oz of oil to the line before proceeding.

I am not a big fan of Harbor Freight but they have the Vacuum system ($40-$70) and Gauges (around $50)
You can also add die to the system to check for leaks.