I make raised garden beds out of 5/4 also. These 12' planks that are on the skids are thinner in diameter so I would use three planks whereas with 5/4 I only use two planks high, 12' long and three feet wide which is the size of the black cloth I put down to inhibit weed growth. So very little cutting except for the end boards. I dig the bottom dirt and turn it over, then fill the raised bed with a blend of topsoil and manure. I save fish racks and freeze them in buckets and then bury them in the raised bed. I then cover the entire bed with the black cloth and cut a slit where I plant the seedling. I use a battery powered drill with an auger bit for digging a hole. Drop the seedling in the hole, cover it over and you are done.
These keeps weeds down and watering to a minimum. If you are planting seeds like for lettuce, beets, carrots, etc. just eliminate the black cloth and plant per the instructions.