In answer to Sleepster's question. No I did not have to use a chin strap. I did however, use the the Respironics Optilife nasal pillow mask which has a strap the goes under the chin to stabilize the mask. It's not really a chin strap, but it may have had some sub-conscious effect on me. I now use the Swift FX with no such strap, and still no mouth breathing.
As far as the nasal gel is concerned, there are two that I use interchangeably. The first is called "Secaris lubricating nasal gel" It is a mixture of polyethylene glycol 15% and propylene glycol 20% in a PH gel adjusted to 5.5. My ENT doctor said that I could use it indefinatley without any harmful effects. The other is called "Rhinarus" which is the same formula as above, but also has sodium benzoate which is a preservative.
These products are available in Canada, but I'm not sure about the US. They are pretty simple formulas without anything weird in them so I don't see what they wouldn't have it.
My wife is a nurse, and she says that this is the product they use for those patients on oxygen therapy.
It works for me. I use it morning and night. It should be noted that I am also a long time user of corticosteroid nasal sprays which may have damaged the mucous lining in my nose.