700 Scale Portholes

For both 1:700 and 1:350 I use a cheap and easy method for portholes. I drill them out with a small drill and pinvise, then dip a toothpick into MicroGlaze or some similar transparent glue, and daub it into the resulting hole.  However, I drill the holes before any painting, and do the glazing after all painting is finished. I do the portholes on the deckhouses the same way.

Since you state that you intend to use PE porthole rims and brows ...

Instead of using CA to cement the PE in place, use something like Future floor polish (Plege with Future Shine or other trade names) or Gator Glue.    Future is good for holding small flat PE which doesn't have structural attachment needs.   Gator Glue is a PVA/white glue with quick grab, yet allows time to reposiiton the part.    Another PVA option may be Aleenes Tacky Glue (a craft store item).    

Future/Gator/Aleene's  all harden slower than CA (even slow gel CA) and allow time to work

Lay a small puddle of Future where the part goes using a toothpick or fine point brush.   Place the part using your toothpick & tack material into the puddle.  Position and allow to dry -- you may need two toothpicks or needles to manipulate the PE.   You can wick away excess Future with a corner of paper towel.   Another small touch of future when dry will seal the part in.  .  

I have used homemade decals for portholes on a 1:500 ship. I laid out a series of black dots in the proper pattern for each area of the deckhouses and hull.  Only problem is that if you use a flat overcoat to coat the decals the portholes are not glossy, but it still did not work half bad.  Should work even better for 1:700.