The right gauge wire for a 12v parallel wiring to LEDS and heat sink
You have two groups of LED strips, all strips in each group are connected in parallel and both groups are also connected in parallel. If you use 12 V LED strips you must use a 12 V power supply then.

If you want to use 12 V LED strips and a 24 V supply, you have to connect two strips in series to the the power supply. You may connect in parallel several of those groups, but only if each group consists of two strip connected in series. Of course you may connect only strips of the same type in series with the same voltage and current.