It sounds like your problem might be non-allergic rhinitis. And sometimes all the treatments for allergic rhinitis wind up making the congestion even worse when you are dealing with nonallergic rhinitis. Google nonallergic rhinitis and you'll get some hits.
The "wind" from the CPAP might be the trigger. Particularly if the congestion goes away during the daytime.
Are you using a heated humidifier? If so, what's it set to? You might find that turning the humidifier up or down may help.
Do you have problems all the time as in 24 hours a day? Or do the problems get better in the morning and through the day, only to return when you start using the nasal sprays and the Neilmed Sinus Rinse bottle and/or masking up for the night?
Pre-CPAP did you ever have any problems with the nose on windy days? What about really wet, humid days?
And finally a suggestion: If the root problem is that the CPAP is drying out your nasal passages and increasing the humidity doesn't help, then you might want to use Ayr Gel or Lansinoh applied directly to the sore, dry tissues inside the nose. Think of these products as "chapstick" for the inside of your nose. You need to protect the tissue from the CPAP air which is chapping it. None of the allergy stuff is providing a layer of protection for your tender, chapped nasal passages.
current settings Min EPAP = 4, Max IPAP = 8 and Rise time = 3
8/1/2010 sleep study results:
AHI = 3.9 [AHI = (#OA +#CA + #H w/desat) per hour]
RDI = 23.4 [RDI = (#OA +CA + #H w/desat + #H w/arousal) per hour]
Dx: Moderate OSA