I just gave W my "expectations" and the toil I went through prior nearly killed me. Listen, I think it's a great idea to set the expectation and it will be a huge relief when you finally do it. But do not sell yourself short because it's been such a dry spell. The ST I talked to on the phone said that you really can't increase the amount once it's been established or it will look like a moving target. I also discovered that the feelings come back quickly once it starts to happen and your need for more attention goes up (at least it did for me). It might be better to shoot high. If she wants to negotiate, then tell her "look, this is not a business transaction...this is the amount of ML that I need to keep my heart warm for you and the family."
For all practical purposes, she's going to have to get her desire back at some point and it will be a lot less work if it's for you instead of the next guy. Her only other option is to grow old alone. If she's willing to accept that or the prospect of a D, then your expectations are meaningless and you should immediately have a "come to Jeezus" meeting with her and negotiate either an exit strategy or a complete revival.
I'm trying to figure out what you "footing" is from your posts. Have you let it be known that the countdown clock is running? I actually had to "shock" my wide a little to get her to see the big picture of our situation by telling her that it's all or nothing time....that I will give 100% if she does. It helped that I was completely disconnected from her prior to this because it gave me the ability to bring something better to the table.