Chapter 6 and 15 "S" ranks?

[skidmarkgn]

After several attempts I absolutely cannot figure out what it takes to "S" rank these last two chapters (6 and 15) and it's starting to really piss me off. Every time I adjust my strategy to raise my grade in time by battle grade goes down and trying to raise my battle grade causes my time to go down. Anyone out there have any tips before I break this damn game in half? I have all the gauges and have been using the obliterator. I've been trying to stay quick but tactical because spamming triangle does absolutely nothing in those two battles. PLEASE HELP!!!

[skidmarkgn]

Update: Nevermind, I finally got them after several more tries.

15 was definitely the more tricky of the two. If anyone's having trouble with it here's what FINALLY worked for me:

First off make sure you don't fail synching his first volley of punches as the inputs have a very small window. I honestly didn't know there was more than one input until my 6th or 7th time playing the episode because I failed it each and every time up until then.

Second, make sure you have unlimited mode always active (I'm assuming you'll have the obliterator gauge equipped) and stay hyper-aggressive. I stayed in his face with :circle: :circle: until he fell then launched a special. Once the burst gauge shows up wait a little bit before activating it and keep racking up combos. I usually kept going until I got in two more specials.

I ended up getting an S for time and Synch and an A for battle doing it this way.