Have you made your decision upon the total amount of coins? Will the distribution begin when mainnet launches?
5M total supply should be, I have seen the 5M is the most popular poll. Good supply, the less the better actually.
It was not official. And I believe 5M is a way too small amount. If XEL has very high price, the one who submits his program to the network will have to pay some unreadable amounts like 0.0010 3170 XEL. It's very inconvenient, imo.
Good point, high supply is good in some points, like you said. This is a good way to prevent unreadable figures. And lower price means lower threshold.