Severance offer, what should I ask for? - 12 months and counting

I was offered 9 weeks of severance after 9 years as a customer-service rep, and I have a few days to sign. This is my first time dealing with any of this. There is a non-disparagement clause. Did anyone negotiate and succeed?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

Thanks for writing this out. I went through something close to it 12 months ago, and it got easier once I kept a simple log of every call and form.