For RC electric fliers, it is important to understand the relationship between electric motors, connectors, wire gauge and current capacity. Below is a chart which describes relation between motor size, current drawn, connectors and wires to be used and you may find useful.
Soldering
It is easy to solder wires to Deans connectors. With a 4-pin Deans connector set, it is usual to combine two pins for a single connection to increase the connection's current capacity. A 4-pin connector gives you two sets of contacts.
The JST connectors are usually supplied with the wires already installed (some called it "pigtail"). You just need to solder the wires into the circuit. Make sure to use heat-shrink tubing on soldered joints to prevent them from short-circuiting.
Wires
Not all wires are clearly marked with American wire gauge (AWG) number. Thicker wires (AWG 12, 13 and 14) usually have its number inked on it every few inches. On thinner wires, you will need to trust that the information provided by the manufacturer is accurate.