@Gnome benzene is carcinogenic and properly toxic. Unless you're 100% sure that your purging process leaves not a single trace of residual solvent, using benzene is seriously risky. As far as I'm aware it's almost impossible to get rid of all residual solvents using basic purging methods.
Especially for people starting out, its best to stick with food grade ethanol as its safe for consumption. Not denatured, food grade. It's more expensive than the other solvents but we're trying make meds here so there shouldn't be a compromise IMO...