As @blujeenz said, the absolute minimum resistance will be 0.28 ohms for 15A continuous discharge at 4.2V (fully charged battery). Ideally what you want to do is allow some room for error reading`s depending on how accurate is your ohm meter is. The lee way is up to you, but in general I use 10% less than the battery CD rating as a safety margin. It might be overkill in some instances but better safe than sorry, especially when you are chain vaping.
