The question of how many frequencies to include in a feed always seems to provoke controversy around here. There are some who want every frequency possible jammed into one feed with the theory that there should be no dead air moments. The problem I have with this concept is that rarely is it possible to hear more than one transmission from a specific aircraft due to the volume of activity. In other words, in cases where there is something out of the ordinary happening (and therefore interesting listening for the feed subscribers), from simple things like a pilot or controller going "off-script" to full scale emergencies, the feed most likely will miss most of the action due to the competing, busy frequencies stepping on the action.
In the case of a smaller airport, my opinion is that less is more. Include approach and tower together so that one aircraft can be followed from takeoff through departure control or in reverse.
The unscientific proof that less is more can be found in the "captured recordings" section of this site. My observation is that the more interesting and popular audio clips found in that section came from feeds that were not scanning lots of frequencies.
With all that stated, perhaps it is prudent to recommend that in this discovery phase you set up your scanner to scan both airports with the intention of seeing if their busier periods step on each other. If you discover that it is too difficult to follow one aircraft's multiple transmissions due to the other airport's frequencies activity, drop back to the airport that has better reception and more activity.
