Will peak at around 280k without sc, 500k+ with (if you have the helms to sustain it).
Depends on how good you are at bone redropping and skele grouping though.
I did it for an hour at 85 ranged just to test and ended up getting only 140k xp :/ I sucked at grouping the skeles correctly.
How did you get to 98 ranging? Whatever you did there, you just keep using for 1 more level basically. As everyone said, chinning seems to be the best, so keep at it.
Should only take you about a day with chins at Atoll, depending on how much you play and how good you are at chinning. Took me about a week to go from 95-99, getting like 250k xp per hour, with no sc helm or void.