I did read the PDF although I have had times when my PC has not been able to read PDF and also when I read them they end up in the cashe so I try to avoid reading them if I can. Hence how I knew there were volt free contacts.
So with new wiring the photo cell will turn it on and the timer will switch it off, although I know it is something to do with load, I don't know if it is switching on or switching off which causes damage to the contacts, but at the price of the timer I would not really worry I would set it up and see how it goes, price of relay and box nearly equals price of timer. The way the timer works unfortunately I would say it is the switching off which is problem, contacts move too slow, switching on however is fast, which is really wrong way around for what you want. However a relay also has a coil it is not a resistive load so timer not suitable for powering relay in theroy. So I would just cross my fingers and be ready to renew the timer if it proves it will not take the load.