The advantage of box joints is the large amount of gluing surface the interlocking pins and slots create. So it only takes a small amount of glue to create a solid joint. In fact, you don’t need to put glue on every surface. I like to use a brush to apply a small amount of glue to the top of each pin. As you assemble the joint, the glue will spread to the other surfaces. One more thing: I apply masking tape next to the pins to trap any squeezeout on the inside corners where it’s tough to remove.