Please direct me to the Casino that has a publicly stated 200% bonus. As far as I know, there is only one reputable place doing so and you said you don't play there. BetUS Does have a publicly stated 200% new player bonus. But this is where I say misunderstandings can happen you think you're getting one thing but you're really not. It's a 150% bonus on sports and a mostly worthless 50% on slots with huge wagering requirements(30x or somthing like that) on gaffed/ very low payback slots locked into the bonus casino. There may even be a cap on the amount you can win from the casino bonus.
The entire host email exchange eerily reminds me of the exchanges I have had with guess who? That's right, BetUS with just different numbers.
I do find the negotiation numbers odd, I have almost never had a host offer me a strange amount like 120%, it's normally 10%, 20%, 25%, 50%, 100%,125%, 150%, or 200%.
Whenever Im offered a low 5x roll its never 120% its normally 50%. Your offers are just drastically better than everyone else's.