Avoid putting PCI cards next to each other and try taking out the spare slot covers at the back of your case which should increase ventilation considerably.
Suggestion 1: Good idea. Spreading PCI cards out is a good idea as the heat does not congregate in one place.
Suggestion 2: Bad idea. You interrupt the natural airflow through the computer that way and cause problems cooling the components in the PC that are not actively cooled. There is a reason many manufacturers including AMD recomend the airflow go from bottom/front to top/back. You remove slot covers and you disrupt the airflow.