Back when I started the process of filing a claim for IU, I used a VSO. What I found is that I was better off doing my own claims work. Some VSO's are more dedicated than others; none are as dedicated as you (if you vow to fight the good fight and don't take no for an answer).
Filing claims is a process. It takes time That's unavoidable. I use to say the VA works on the premise of attrition. Frustration or death being their targets. Having vowed to not let frustration get me down and outlived their resolve, I finally got my IU after seven years and two separate claims,without a VSO.
What was helpful was the support received from my doctor and from the VA's Voc Rehab folks.