Nasal pillows

I would really like to give the dreamwear mask a go but during the day I'm generally a mouth breather. Is it at least a possibility that when asleep and wearing the nasal mask that I would revert to nose breathing without a chinstrap? Enough of a chance that it would be worth investing and giving it a try?

It may depend on the reason you're a mouth breather during the day. Allergies? Deviated septum? Habit? etc. If there is a physical reason why you don't naturally breathe through your nose, you won't be as likely to overcome that just using CPAP. Now, if you have allergies that cause swelling and congestion, using one of the fine filters and breathing filtered air could theoretically reduce the swelling. If it is a deviated septum or other obstruction, you would have to decide if using a nasal pillows mask is worth having repair work done. If it is a surgery you would need, you could search the forum for previous discussions or post a new question here. That topic seems to get quite a few responses.

Thanks. Sorry should have said, no physical reason I'm aware of that I can't breathe through my nose. More habit.

get the chinstrap

It will help reduce the leaks thru the mouth when using a nasal mask

other than that, go for it.
worst case, it doesn't work for you. in that case go back to your FFM and move on.

If you buy the mask from cpap.com you can get free return insurance. So that if you decided that it isn't working for you within 30 days, you can return it and get what you paid for the mask back. This lowers your financial risk.