Don't really want to go on too much about TCX on a GSM thread, but I'd be amazed if either GSM or TCX offered 35 inch pitch in 'cattle' / 'Y'. You won't normally find many of the regular scheduled airlines operating across 'the pond' offering > 32 inches, i.e. BA, AA 31 inches.
I can't see that even with the intended 189 pax config. will result in a universal 35 inch pitch, more likely just in a smaller premium section & 31 inches in the remaining section.
Incidentally PTV systems in BA for example are mounted under the seats, and even on BA in 'Y' the seats and any comfort compromise is minimal, and still better than current IT offerings.