Welcome to Healing Well!
Right before you have the Manometry, be sure to tell the MD or Technician which nostril you would like the probe placed. Some people, like me, have a deviated nasal septum which necessitates going in from the left side. Also make sure that they use enough lidocaine (or similar) to make the procedure more comfortable for you.
A bottle of spring water would be good as well.
Please post back with the results of the Manometry.
IMO, if a reduction of BMI makes the difference between having the Linx or NF, don't rush into anything yet.
P.S. Are you really an RN?