To save searching around do you have the flow rate of your products? If so then if it totals around 10 x full tank turnover per hour then you'll be fine, just make sure the equipment all compliments the flow from all other equipment.
Both at the same end is by far better, sorry but its true as the flow circulates the entire tank then, along top, down the end of the tank to the substrate and drawn back to the intake. Look at any aquascapes that have left filter pipes in for the photo mate or go to a Takashi Amano vid on youtube.