Yeah, wait till things calm down to change anything major/expensive.
I assume you had your claim in within 1 year of getting out? You'll get back-payed from the day you got out then. Make sure you get evaluated on every damn thing
that's bugging you, and add your back and knees even if they don't bother you much now. You're a grunt, so your back and knees are going to be fucked up. I have 20% on my broken ankle, and 10% on each knee, for 40%. My spine is a train wreck, but I didn't think to have them check it when I got evaluated. Started seeing a chiropractor shortly after, who took x-rays, and got copies for myself so I could take it to VA. If VA rates you 50%+, one more piece of paperwork will get you 50% Social Security, as well.
I haven't seen any evidence of VA lowballing, but you do have to sell your pain, and that's an odd thing for most vets to do. Especially right when you get out, as your still used to an environment that shuns whiners and malingerers, or anyone that could be considered one. It's important to mention that, as a grunt, stuff is more of a problem in the field, where noone can record minor injuries. Every grunt I've known has self-medicated in the field. I always carried 200mg Advil, cuz that was my miracle drug. I shared it with my whole squad. The Infantry can't even get out of the prone without Ranger Candy
I think a lot of guys get worn down by the layers of BS when you go through VA, but remember that it pays for your whole life, and goes up with each dependant. Do it right that first time, get everything evaluated and rated, and you'll be set. Then, if shit gets worse as you age, you can get it upgraded, but that is wholely another PITA...