OK. Here's a schematic that should accomplish what you want. (The .pdf is attached as well if the attached image is illegible.)
In the case of pumps, there is no need to use an SSR. You can use a relay with a 5V coil. SSRs are only needed where the circuit will be switched on/off frequently, such as in the case of a heating element in a BK or MT. Although, there is nothing that would stop you from using an SSR instead of a relay if you really wanted to.
As for gauge, for the pumps, you may use 12ga and for the relay coil wiring, you may use something as low as 16 or 18 ga.
If you have any questions about the schematic, don't hesitate to ask!