AHI Differential

OK, I am finally sub 5 AHI with a F & P Flexifit 407 Nasal Mask and Premium Chinstrap. The AHI range is 3.2 - 5 with average leak rates for the mask.
Now, I have been experimenting with Full Face Masks to be used either as a back up or when allergy symptoms hit. The only FF that works for me is the F & P Forma (or HC 432). Benefits of the FF, more predictable stable leaks, an AHI about 33% less and no severe cotton mouth that I get from the Nasal Mask.
The downside is the extra itching, bulk and heat generated. Also, the forehead seems more uncomfortable (I will try a Pad a Cheek).

Is it worth the sacrifice of a bit of AHI and comfort? Is it better to just use the FF and get the optimal results or enjoy a bit more comfort with the Nasal Mask?
Thanks to all!

Try one of the hybrid-style masks; they are considered FFMs as they cover the mouth and have nasal pillows -- works great for me when allergy congestion completely blocked both nostrils, just a bit of dry mouth as I usually had pre-CPAP. Choices are RespCare's Hybrid or ResMed's Liberty.