Regarding pricing have you explored whether or not companies W, Y or Z might be interested in buying your product? Until you explore other buyers you are limiting the range of offers you may be able to get. By only entertaining what company X might buy this for you have already agreed to a price range which is $some amount of money that's an obscene deal for company X to $the maximum company X might be willing to pay…
Assume the deal will fall through and plan accordingly, whether that's through a provision in the term sheet (like a cap on lawyer fees or a penalty for walking away from the deal), or working something out with your lawyer.
Related: deals do fall through.