The usual thinking is for the fan to be behind the rad to suck air through. Based on it blocking airflow through if in front. The fan kicks in if the sensor teaches the designated temperature for the engine cooling system. There is a chance of the fan kicking in more often if the temp rises more frequently due to airflow restriction. As for the through the rad fixings, if your rad is in good condition then there shouldn’t be any problems. If in doubt use brackets to fix off the rad but make sure you don’t create big gaps.
