10 bill coin, that much? It would be better a 10 mill. i think.
I'd prefer 1 trillion. Min price is 1 satoshi anyway

So at the min price cap would be 10'000 BTC.
But if seriously I think 10B coins is the right choice. Nxt has 1B, shitcoins have 100B, so 10B will work just fine.
I don't understand your logic:
You prefer 1 trillion (1,000,000,000,000)
100B = shitcoins (100,000,000,000)
10B coins is the right choice (10,000,000,000)