drill rig metrics

Approximately what is the cost per drill rig for the drill rigs #3 and #4 that were just added to the fleet?

These drill rigs are adding about $5M to $5.5M of revenue per six months. Assuming some down time each year let's assume $7M per annum, conservative. How much EBITDA is added per drill rig?

I'm trying to get a sense for how much debt and interest we might need to pay per rig, and will the company have any free cash flow left after paying financing and operating costs?