Not 100% sure about XP rates - you could make a whole entire guide about chinning to be honest.
Just off the top of my head (it's now been almost a year since I was there), 300-400k/h xp seems reasonable, with grey/red chins, at 1,400 chins an hour approx? So for about 25 hours of chins, you're looking at, say, 37k chins (fewer if you're using red chins) and enough pray pots to sustain yourself.
It's one of those really - it depends what chins you're using, whether you're good at chinning and will focus on screen to make good piles (and whether you die lol!), what your pray level is, what gear you're using, whether you'll be using +10% range pray.
@Paul`'s suggestion of 60m sounds about right to me. You're probably looking at 45m-70m depending on the factors above.
Maybe you can drop back your answer when you're done @Creamman so others can use it for reference later. Welcome to the forums and gl on app to Foe.