Yeah, just DI/SDI behind marth and it'll be harder to get utilted a billion times, just be wary of them ending their string with fsmash, because that can happen, so you should be ready to survival DI the tipper.
Game 2 on FD Mango DI's behind marth pretty well, but gets fsmashed pre-emptively. Better than being off stage with 20-30 more percent I suppose. He does this at 34% on his second stock.
https://www.youtube.com/watch?v=MoUgDqrmhIA
Game 2 on FD, 2nd stock Mango DI's the first utilt either up or away from marth, but once he reaches 52% he DI's behind marth, outside of tipper fsmash range. Technically mew2king was supposed to shffl uair to regrab at that percent I believe, so that's why DI'ing utilt behind was so effective. If you're opponent has a habit of doing utilt regrabs from 35-59 (which is the range you're supposed to uair regrab on fox) then waiting until this percent range might be effective.
https://www.youtube.com/watch?v=7U1pZFOG_HI
Here is a thread with the marth v. fox chain grab tree for reference (falco's is +8-10% onto fox's I believe):
http://smashboards.com/threads/compilation-of-matchup-guides.341532/
I believe if they do their chaingrabs perfectly to the T (probably won't, but you never know), then you basically either have to DI towards a platform to escape or if it's on FD then you have to SDI up on the uairs in hopes of being able to jump out