Thing is, most RDA`s that I have used would just suck at 1.3 or higher. To really get that RDA experience you need to go below 1 ohm.
I have .7 and .4 ohm RDA`s right now and steam engine is telling me the .4 is using about 44 watts, so I would think at least 50 watts to get that thick juicy cloud a RDA is known for.
Not saying a 1.3 ohm cant be done well, I just don`t think it would be worth it in my experience. Maybe a smoke-tech or similar single coil RDA would be OK, as long as its really small, but you would still want to go closer to 1, maybe 1.1 or 1.2 at most.