4th is fine. 6th is more complex. firstly, you have no fold equity because he is never passing aces. looking at the numbers, there are 33 unknown cards, so you need to have more than 16.5 outs to have bet odds, you have 14 outs to trips or better and an additional 9 outs to 2 pair...so if 2 pair is enough more than 1/3 of the time, betting is +EV.
7th street, pure math in a vacuum he's about a 60% favourite to have aces up or better so you should check. he has an A, 3 or 6 (6 outs) in the hole 47.6% of the time, and a pocket pair something like 12% of the time (26 cards are accounted for at this point, so there are on average 2 of every rank, he has 3 hole cards, so on his 2nd card he pairs his first card 1/25, and on his 3rd card he pairs one of the first two cards 2/24, so ~4%+8%=12%, this is extremely rough math, but it's close enough to be sure which action is better)
so, revisiting 6th street, knowing that he is going to have our 2 pair beat 60% of the time, those 9 outs to 2 pair count as about 3.6 outs (each of those 9 outs is good 40% of the time, 9*0.4=3.6). this gives us a total of 17.6 outs in 33 cards, and correct bet odds. disco. but there is a caveat, which is that to flat ??A, he actually does have a smallish wired pair more often than he would by pure math, he shouldn't be playing a hand like 8s3cAh, but he is coming along with 7s7cAh. 6th street is pretty close anyway, so it's not like you're making a colossal fuck up if you get it wrong, you're only giving up a fraction of a bet.
i'm bound to have said something stupid in there somewhere, but at least it will spark replies. in answer to your other question, the old 2+2 stud book is a pretty good place to start, it will at least give you some things to think about.
Kc
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"Blah blah blah KC is right"  Ozone
