How to prepare for potential job loss/redundancy

oopss

There has recently been a large number of redundancies in my place of work - supposedly vol but most people who took it were advised to take it. They were long servers, high wages due to an index linked pay deal / union deal. I have a very strong suspicion that they are about to do similar to myself or my team. My boss is already hinting and I know he will protect himself at all costs.
I am not a union member & I want to be prepared. I am realistic and know that if the decision is made to offer me vol redun, that I will have no choice.
I am of the belief that in the recent VR scheme, people did negotiate additional payments but I have no evidence - based on overheard conversations of senior managers.

My questions is how do I prepare for it /where can I get advice (a web search has left me none the wiser)
....if I decide I want it, how can I maximise my offer
..... if I decide I don't want it, how do I fight it

Important to note, my role is not redundant based on current business plan, unless my boss takes it on (a board director - he wouldn't know where to begin) and it does produce return on investment.

Any advice on what to start thinking about/how to prepare/inform myself would be really appreciated

thx & regards.

InReality

Could you talk to any of the managers who might have negotiated theirs ?

oopss

Have tried but my guess is that deals have been done and there has to be confidentiality clauses. None of them are close enough friends to ask outright .
But thank you for suggesting.