I think you would be fine with usin flats - I still use them on DS when he has a case of the runs.

Just get some awesome covers - you should only need about 4 PUL covers - depends if you want to use cloth overnight as well.

I wouldn't personally use flats of a night time if he is sleeping through. Although by your posts that I have read - that won't be a problem.. LOL

Then if you get really awesome covers (ie, like Mother-ease) you can resell them cos they are awesome awesome covers.