Pretend that they are going to sue you, and you have to get every document/email/agenda that is even slightly relevant into evidence within an exceedingly short timeframe. Because when you sue them, that's one of the first things you'll be requesting from the court, and in turn it is one of the first things they will do in response. This process is known as 'discovery' and if the stakes are high enough it can get quite abusive, ie ridiculously wide-ranging requests that are designed to make the litigation process as expensive as possible. If the other company is much larger than you, they will try to spend you into submission. Likewise, they will want to bring you into their offices for lengthy and unpleasant depositions, and your lawyers will try to do the same to them, which they will fight.

I presume you're waiting for your lawyers to call you back, because this is why you have lawyers in the first place. You might as well sit down with your accountants and start trying to quantify the gap between your best and worst-case scenarios in order to get a handle on your economic loss and establish what the efficient settlement price is. I'm only a law student so I can't give you any real guidance, other than to avoid becoming emotionally invested in who's right or wrong.

PS: they might sue you anyway, if the economics makes sense. It's not unheard of.