I only have a 1070 card in my testrig. With the opensource i can reach 275-280mhash with oc. My private kernel oc around 100mhz higher than the opensource so you get an additional 5% from the oc. 305-310mhash stable.
Receive a 5% increase and give 3.3% + 0.1 BTC - it's not fair.
You see, removing the initial payment of 0.1 BTC, you will attract more people who will bring you income. For those who have 1-2 cards in 1070 are not ready to buy your miner. Payback tends to infinity.
You will not hear the angry responses of those who gave money, and who were not satisfied with the speed of your miners. Using the "as is" - you will not reproach.
Claymore has made the right decision, and it is a success. You will stagnate.
Do 2% with no down payment, and earn more.
You are a good programmer, but a bad marketing.
PS. sorry for my English.