I heard it has a lot of glitches with rock crabs but I never tried so I'm not sure.
However if you have some money left over, try buying the AutoCrabber Pro.
Make sure you have your current tile set..I couldnt figure out what was wrong with mine after I bought it, but that was my problem. It will not do anything unless you have your current tile set.
Go try botting at al-kharid warriors, that's where I usually bot for great xp.
However after I usually get a combat skill to 60-70, I soulwar it from there as it is much better.