Training Reference Guide for Thieves.

Regarding chief bandits, from level 72 (meso explosion+gaurd)-level 10x, the best exp your gonna get grining (aside from leeching maybe) if himing with a priest. bombing himes basically kills 12/13 of the monsters on the map instantly, every mob. thats 38400 exp per mob=pro exp. After that, bombing skelegons isnt that bad solo if you have 6 hit BoT, and after that, bombing gobis is alright. If you do himes/gobis the right way, you can break even/gain money while bombing (although sadly you need a pet to loot monster drops, otherwise its easily just to blow up the mesos monsters drop), and I doubt meleeing can be any faster at LEAST until 10x.