My VBAC advice is to find a local ICAN chapter and start attending meetings NOW. I've never had a cesarean, but the women there are such an amazing resource!
As for RRL tea, here is my 100% non-scientific anecdotal opinion: I've given birth 3 times. The first time, from 30 weeks on, I was pretty darn diligent about my cup a day. I did have (unrelated to the RRL, it was from an infection) a stint with pre-term labor, but the actual birth was great. First time mom, 9 hour labor (which probably would've been a 6 hr labor, but I stalled a bit in the hospital from being anxious, poked and prodded, and not wanting to be there). I had very little pain as long as I was in the water and could move as I wanted to. The only time I asked for any kind of pain relief (narcotics, which I should have known wouldn't work!) was when I was stuck in bed for monitoring because it made my sciatica act up. Forget the contractions, my butt and legs hurt!
Second time, not big on drinking it. 6 hours of labor, 3 hours of active "this is really it, not just the prodromal stuff like always" labor. Back labor, so painful. Birth was still easy, but definitely not as pain free.
Third baby. No RRL at all. 2 hr 10 minutes of labor. Woke with a contraction, baby was here 2 hrs later. Easier than the back labor for sure, was able to move, use water at home, etc. Still, not as comfortable as that first time.
Was it the RRL tea that made the first time so much easier, or just the fact that the progression of labor was a bit more spread out? Not sure. But I've already started drinking it again this time. I make a liter of RRL soda (I have a sodastream soda maker, which carbonates drinks). I make a mug with 3 tea bags in it. Then I add water and lemon juice to fill up the rest of a 1 liter bottle. Carbonate it, and drink. It's fizzy, refreshing in the heat, and tastes good! Once it gets chilly out I'll switch to drinking it hot with a little bit of honey. I will likely look up the RRL infusion to have on hand for labor, and maybe some RRL ice cubes since I have a hunch this will be a longer labor.
I figure I like the taste, it's been used for the purpose for centuries. If it even only has a placebo effect, hey that is sometimes just as good as a real scientific reason. I'm big on 'if it doesn't hurt and may help, why not?' reasoning, though.