According to the Honda repair manual for the 1995 Civic DX with a Sanden
compressor, the system oil capacity is:
6.3 oz of PAG oil total, but the condenser alone should have .7 oz in it. If
the condenser has been leaking you may have lost some of the oil from the
rest of the system as well, so there is no way of knowing how much is left
in the system unless you remove each component and drain them separately to
see how much comes out.  Other than that, you could flush the system to
remove all the old oil and refill with the correct amount for the total
system. If you want to avoid flushing or removing all the components and
would rather guess, then add .7 oz to the new condenser plus another .8 oz
to allow for what might have leaked out.
The most complete and proper repair would be to remove the dryer, the
compressor, and the leaking condenser. Flush the rest of the system, drain
the compressor and add 4.3 oz to it before reinstalling it, then install a
new dryer with 1 oz in it, and the new condenser with 1 oz in it. Pull a
complete vacuum for 90 minutes,  then add 17.6 to 19.4 oz of r134a
refrigerant  until the operating pressures are correct at 1500 engine rpms,
for the prevalent ambient temperature and humidity, providing all other
system components are operating correctly. The Honda repair manual has a
chart for desired high and low side operating pressures at various ambient
conditions. You might get a Dealer service department to print you a copy if
you ask them nicely.