How long after recharging fridge until expected temps are usually reached? (Frigidaire FRT21P5AW7)

[Lee Butcher]

I have a Frigidaire refrigerator that started losing its normal cooling temps a few weeks ago. It was to the point of the freezer keeping the ice cubes frozen, but solids (meats/frozen vegetables, etc) were half frozen or thawing. When I pulled the back freezer panel, I found icing on the lower part of the coil and up around the thermistor and the lines around it. 

I first cleaned (blew out) the condensor coils, checked the compressor, which is running and warm, and the fans are all working. So far I've replaced the defrost thermostat, the compressor start relay and the run capacitor. After giving it a day to see if this would help (it didn't), I went ahead and vacuumed the old refrigerant out and added the prescribed 4.2 oz of r134 freon. I found when I was finished charging that I have a bad seal in the connection to the 12oz freon can hose, so I'm not sure if it got the full 4.2 oz or not. 

I've been monitoring the freezer and fridge temps since finishing the evacuation yesterday, which started out as 63*/freezer and 59.5*/fridge. (I had previously defrosted the freezer coils and put what was still "frozen" in the freezer into the fridge). The temps slowly and steadily dropped from 11:30am with a single uptick from 1:15-3pm of 41* to 43.5*, then down to 39.2 at 4:30pm. (These are all freezer temps). It has continued dropping slowly until my last check just now at 11:20am, 24 hours after adding the freon, and is now at 29.1/freezer, 45.5/fridge.

This fridge is 20 years old, but it was bought as an appliance set when purchased. We plan on selling this house in the near future, and although the appliances are 20 years old, the rest are all in good condition, and we really don't want to change out the whole kitchen if I can get this repaired so as to keep a matching set. 

My question is, how long should it take for this refrigerator to reach it's normal operating temps, and what are the usual temps for that level?

Since I had a bad seal and am not sure how much refrigerant actually made it into the system, I'm hesitant on adding more (too much), but I want to get this thing running correctly. Thanks in advance for any answers to these questions, and any suggestions or help in getting this done. 

Lee

[Lee Butcher]

Forgot to list the new defrost timer was installed, too.