Don't have any experience being a warrant officer, only have experience wishing I were one and experience being around them. KiowaPilots.com has a LOT of information that will answer some specifics you have. Make sure you utilize the search function and I would recommend not posting there for a while.

I would recommend talking to some guard pilots in your area about their experience. The AD and guard road to flight school is a little different.

As a ballpark, most WOs in my OH-58D class had AFASTs between 120 and 140. This really isn't a significant portion of the packet from what I've heard. I had quite a few LT buddies who got in the 90s. Prior flight experience definitely helps...PPL-commercial, either way, shows you are competent enough to make it through and have the desire/discipline to apply yourself. A lot of the AD people I knew in flight school who got picked up the first time they applied had at least a private ticket.

Any specific Q's feel free to PM me or any of the other army pilots on here, i'm sure people can help you out.