What is "Two in hand" coil winding ? How does it affect the inductor?
"Two in hand" means you have 2 wires in parallel when you wind.  This doesn't necessarily mean  they are wound at the same time in parallel, it could just mean as you say above that they are connected at both ends after they wind.  This is very often done to aid in manufacturing so that they can wind with a lower gauge wire.  If 18 gauge wire is too big for your manufacturing processes, you can go to 21 gauge wire, two in hand.  I've seen low voltage motors that are wound 3 in hand and 4 in hand.  The inductance and resistance aren't significantly affected. Yes, you would use the same number of turns.