That's exactly what I do. There's a lot of tension on the cap with the O ring by itself, so once it fully seats it is either sealed or not. I didn't use a torque wrench the time the time that I did it, at this point I don't see a reason to.Have done the job twice so far. I just slowly tighten it until it seats. That, along with the rubber ring gasket, keeps it in place. I always try not to overtighten plastic parts.
I had to do some digging to find the torque spec, the instruction procedure for the oil change said to refer to general engine torque specs, of which there are about 30.