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@Mushin said, check with your legal aid folks, and check with the DAV and American Legion. My memory (from almost (yikes) 30 years ago) was that TECHNICALLY it was NOT an adversarial process so you aren't entitled to representation, but...you bet your ass it was adversarial, in that they were gonna screw you somehow.
If the military gives you a disability rating, then it comes out of their budget. If they give you a low rating (like, nothing or "0%") and then pass you on to the VA, then the VA has to pick up the bill for your disability rating for anything over that 0%. So, you can bet that the military doesn't want to give you a high disability rating...but if you are really disabled, and you need the money because you will have problems with getting fully employed in the civilian world, then, you have to wait your turn in the VA process, which can take a couple of years.
From what I have heard now, there is better integration between the military boards and the VA (honestly, it couldn't have gotten any worse...) But essentially, if you are being brought to a board, they must have some percentage disability in mind they will offer; you want to make sure that the offer is based on some reality of your situation. Find out what you can about your current job, what you can/can't do, the alternative jobs in the military, and then the equivalents in the civilian sector.
FYI, your disability rating can increase, over time, if your injury / disabiliity or whatever progresses...this is quite normal, so even if you don't get that 70% rating at first, you can potentially get it later, as you age & the disability gets worse.
Finally...this is a real stressful period, find some ways to keep your perspective, and don't let any a-holes pull any mind-fucks on you. Reinforce your ties with your family, as you will undoubtedly need their support.
I was in the military ages ago, end then I worked in a VA hospital for a couple of years. I've seen a couple people go through this process. This is the worst part of the process. Once you are out and plugged into the VA system, people typically are very happy with their care. The problem is the x-number-of-years time it takes going from getting discharged, to getting the VA Compensation & Pension review/rating, to actually getting enrolled in the VA care. Whatever you can do to smooth out that process & shorten it will help you in the long run.
Good luck! Don't be shy about posting about any other questions, or what you find out!
