Honestly you need 1.5 to 1 and like 12 cells on the titans with the motors in parallel to get reasonable prop rpm without load. With a setup like this a octura x440 or a x442 should work, graupner k series prop should be a close substitute for the octura's cheap and don't need balancing. I don't know how long the motors will last with this setup but if you want to use the gear box this may be the right direction. I think a single 700sc or 700bb 8.4 would be a simpler, more reliable and more convenient if you give it a try.