An alternative to crimping multiple wires together or soldering is to run an individual wire pair to each brake location. The four individual pairs are then terminated on the tongue on a terminal strip. The terminal strip is installed in an enclosure and the umbilical from truck is led into that enclosure to connect to the brake wires. Terminating using a terminal strip and using this Star layout gets the most power to each brake and makes diagnosis of brake problems easier. Any electrical issue can be diagnosed at the tongue.
I have all of my trailer wire connections on this strip: