[cstreit]

If you’re going to use plastic surface mount boxes, be sure to include a ground wire (separate from neutral). Inside the wall systems use the metal conduit and boxes as the ground. You won’t have that.

Number of outlets is irrelevant. Power draw at any given time is the factor.

Solid is always better. Stranded works until things get hot, it corrodes much easier. I’ve seen more issues with stranded than solid.