I'm not looking for guidance on any specific Tower Defense game, but a general strategy for those TD games that allow you to place towers anywhere on the map to form the maze, such as Xeno Tactic, Robo Defense, etc. There are a lot of walk-through/guides for these games online, across which a few common patterns can be identified. However I couldn't find any article that compares these patterns.
Is there one or few patterns that could be much more effective, in terms of damage output, than the others, or all patterns are similar as long as there are no obviously wasted room? I am looking for answer/reference to a comparison of the patterns backed up by mathematical analysis or experiment.
This question is not asking how to build the longest path, but rather, whether longest path is the most efficient and why. Path itself takes space, so when the path is longest, the number of towers on the map isn't maxed out. Is it possible that the total damage is higher with a shorter path but more towers on the map?
Even if the longer path the better, there are more than one way to build the long path, which I do not believe are all equivalent. Is there one pattern easier to start small and expand along with game progression than the others? Is there a pattern that is advantageous than the others when it comes to dealing with long line of enemies? Some say the 'twist in, twist out' pattern (see screenshot below) has the max utilization of the tower coverage, is that really so?