Standard procedure is to replace the accumulator and orifice tube whenever the system has been opened to the atmosphere and/or has been non-functional for some time due to low freon. With it getting close to 3 decades old, it probably wouldn't be a bad idea to replace all the rubber hoses too.
If the original compressor locked up, it's also wise to replace the condenser (in addition to the above), as it is essentially impossible to flush the debris from a failed compressor out of it's many passageways, and anything floating around in there is likely to ruin the replacement compressor.
Since your replacement compressor is new, it was probably designed to use PAG 46 oil. I suggest using that with R-134a (of course making sure all traces of the old mineral oil is flushed out of the rest of the system). Ester oil is generally used if the compressor itself has already been ran with R-12 & mineral oil.
Finally, check that your compressor wasn't shipped with oil already in it (many are). I would recommend draining whatever is in it and start with new oil rather than mixing oils (that is unless it was clearly labeled as being shipped dry).
On this R-12/R-134a charge ratio thing...
When I had a shop charge my '90 BII years ago, the guy (who seemed knowledgeable) explained to me he puts in the same amount (weight) of R-134a as you would R-12, and that he has not had any issues doing so (but charging to a lower weight had brought many complaints that it wasn't as cold as it should be).
Indeed, I have seen temps as low as 36° out of my vents (generally it hovers around 42-44° or so if it's real warm outside and the blower on max). I don't recall if this is something specific only to Fords of this vintage, or if it's for all R-12 - R-134a conversions, but it would seem to make sense that it could be a source for the common complaint that converted R-12 systems are not as cold as with the original R-12 (certainly if mine was any colder, I'd have issues with the evap freezing up and blocking the airflow).