Just skip the part about guaranteed BTCs, just call it the "$1m guaranteed". It's especially true for this particular tournament but I think you should stick with this policy for the rest of the tournaments also.

I'm not trying to be a smart-ass here, I'm just trying to help you out. Both players and you, the house, can get into alot of ugly spots and arguments if people start referring to these guaranteed BTC prizepools. Think about it.