If I understand what you said,two 120v in series will work fine. They should be identical,otherwise both will aluminate at same wattage as smallest lamp. You said it is 2 wire service. If that's two 120v wires and no safety ground wire,you can tap 1 of the 120v wires then drive a rod for neutral. If it's same 240v single phase as we have in USA,you can tap bare/green as neutral. Both jerry rigged 120v present a possible shock hazard to the unsuspecting so would not meet code around here but it works.