Datacenter availability, that's an interesting tought.
I agree with your post and we don't have any solid data so this is all going to be guesses of some sort.
22PH for BFL in Q2 could be a good guess (on the safe side I hope).

Do anyone have any ideas about Black Arrow? I read somewhere their first batch was going to be 8000 units, sounded like a lot of units/preorders to me at least if that meant the number for X-3 since I think they are now on batch 2. Anyway that's 16PH in Q1 if all is going according to plan. And maybe another 16PH for Q2 for batch 2. But I have no source for this.