Advice on full face or nasal for titration?

When I went in for my initial study, they test fitted both a nasal mask and a full face. Both seemed comfortable they had the adjustment knobs that allowed me to get the pressure off my nose bridge. Tech asked if I was a mouth breather which normally I'm not until I snore. She suggested starting then with the nasal mask, & if I couldn't sleep with my mouth closed, switching to the full face. We never got to the titration phase that night. Going back in a few weeks with a stronger dose of AmbienCR and another go around. I've been thinking, since I'm easily disturbed and have difficult falling back to sleep once awakened, perhaps it might be better if they start with the full face to get the titration levels, then if time permits, switch to the nasal to see if it's an option. Less possibility of sleep disturbances, open mouth etc. affecting their data collecting. Good logic? Really don't want to go through this again.

I sleep on my back for the most part and sometimes on either side when my breathing gets labored.

I'm no sleep tech, but I'd think the one that produces the least leakage would be the best for titration. One less variable to deal with...

I'd also think Ambien (or any other sleep aid) could skew the results, but what do I know?

My sleep doctor regularly gives Ambien CR rx (7 day trial pack) to help with "first night" problems during the sleep test. When I asked if it skewed the data I was told that it did not. That there were some sleep aids that did but Ambien wasn't so bad. For someone with problems getting to sleep anyway, you got to take something or no sleep and if no sleep, no study at all.

I used nasal pillows during my titration study. I initially tried the nasal mask but it gave me a headache so I asked for the pillows. Tech squawked about my choice saying I would leak too much for good data. I didn't. I did great with them.

If you are really concerned about not being able to get back to sleep if having to change to full face mask in middle of the night, why not lessen that worry and just start with the full face since it seems comfortable enough for you?
Our minds race enough during these sleep studies, no sense in giving it more to think about and keep you from getting to sleep.