I reckon you're good to go Luv, I really do
If 6mm's is good enough for Monash over here then I say go for it and I agree that you've thrown everything at it that you can so I don't see what else you can possibly do??
I honestly believe it's thick enough Luv for the 3 Amigo's and the Progesterone will fluff it up nicely for them to settle into for the duration I can see why you feel such a sense of responsibility toward them so ultimately the decision is yours on whether to cancel or not.
Don't worry about falling behind on the posts for frucks sake!! You've got bigger fish to fry at the moment!!!
I just hope Dr M over in CT comes to the party and says yes or just leaves the decision up to you.