the capital cost can to a large extent by expressed as a performance/density figure, GH/MM, and the operational cost expressed as a Power figure W/GH/S (aka J/GH). the remaining system costs (fans, power supplies, pcbs etc.. are largely constant regardless of the silicon used, so the main factor is efficiency and cost of the silicon itself)
Possibly. You still need to know the ratio of silicon to other system parts costs. If a $100 miner is made up of $1 worth of chips, and $99 worth of other parts, doubling the cost of the chips only makes the miner cost $101. Unfortunately I don't know how much the raw chips cost to know if it significant or not relative to total system cost. The silicon could be a significant portion of the total system cost by now. It didn't used to be.