I have never really done a sub cooling in my life. Only in school.
I forgot now what your sub cooling should even be.
The first co I ever worked for we used superheat to charge. Now, I just go by the charging table on the unit. 95% of the units I work on are 5 years old or newer tempstars. On their charging chart, all they want is indoor wet and dry bulb temp, and outdoor drybulb temp.
I used to have a card telling me what superheat should be at different ambient temps. I really should get one again and start checking sub cooling.
I ran into one just today that had a 325 head and 70 suction. Cleaned the coil and all, still can't get that damn head pressure down.