Best way to do it: end game removing all characters in camp and leave the game and save off characters (press "Enter"). Start the game without loading saved progress, add to party character 1, which has item you want to clone, and character 2, which is supposed to havet it. Being still in camp, give item from CH1 to CH2, remove CH1 and enter wilderness (CH2 is saved), return to camp (don't save game outside camp - when game is saved manually, every character is saved - in party and also that left in camp) and continue cloning - give item from CH2 to CH3, remove CH2, enter wilderness with CH3 only, go back and so on. End cloning removing all characters in camp and leaving the game.
On C64 version, cloning also works, but in different way. Game saves characters not when leaving from camp, but when removing from party. So make it this way: add members to party, give item from CH1 to CH2, remove CH2 (game saves it), then add CH2 back to the party, give item to CH3, remove CH3 from party and so on. End cloning, leave camp to wilderness and then end game (without saving it). After new start of the game and adding characters to the party, they have items, whose they have when removed from party.
Described process is best for cloning Harmonic gems, therefore party has no problems with SP.
