not add another input, but you can concatenate the size to the name input, just after the Item Number hidden element is one for name:
php:
<input type="hidden" name="item_name_<?php echo $SecretWishes_Index+1; ?>" id="item_name_<?php echo $SecretWishes_Index+1; ?>" value="<?php echo $SecretWishes->DisplayInfo("Name") ?>" />
you can add the size to the name value:
php:
<input type="hidden" name="item_name_<?php echo $SecretWishes_Index+1; ?>" id="item_name_<?php echo $SecretWishes_Index+1; ?>" value="<?php echo $SecretWishes->DisplayInfo("Name") ?> -Size: <?php echo $SecretWishes->DisplayInfo("Size") ?>" />
