"solid wire carries current better than stranded"
BUT isnt stranded wire just a bunch of smaller SOLID wires all bundled together????
Stranded wire is used for its flexibility and vibration resistance properties.
At DC or low frequency AC the so called "skin affect" isn't a consideration like at high frequencies where current tends to flow more in the outer perimeter of a wire.
The cross sectional area or sum of all the cross sectional areas is what determines a wires rating to carry x amount of current.