I choose to print it vertically (cutting the edge a little bit to make it stick to the bed) because in my opinion I achieved the best results. In fact, if you print it horizontal, with the back of the coin on the bed, you had to set the minimum layer height your printer can reach to show the details. Otherwise, if you settle to had a cutting edge, you will sure have all the details emerging, and still with no supports. I print it in vase mode, infill 0%, layer height 0.05mm, nozzle 0.4, with white PETG from REAL that gave it the glossy finish.