We provide two sizes for our EFHW antenna models, the 16AWG XLPE for 1K models, and 14AWG XLPE for 2K models size wires. The 16ga wire is easily concealable (For any HoA concerns) and has a tensile strength of ~100lb (45kg).
Always make sure that any installation involving moving trees has enough sag and not too much counterweight if a pulley system is used otherwise the flex in a swaying tree limb may snap your wire!
The 14ga wire is considerably stronger but also heavier with a larger surface area which can accumulate more snow or ice. As detailed in this QST article about wire size, wire strength ultimately depends largely on the installation and sag amount you are going to leave on the wire.