How would a coach go about game planning for the unpredictable? I'm talking opponents who make constant lineup changes as great as playing 3's at 5 spots or 1 to 3 spot.  Would the best option be to a.) just put the team out on the floor you think has the best chance of dominating a particular category? (i.e. rebounding, def stats, off stat) or b.) play a guessing game of where you think the opponent will start certain players? 

Unless you can spot a pattern (eg. always plays the 3 at 5 vs Press), I wouldn't try to outguess someone who constantly makes changes. If you have been consistent with your lineup all season, you may want to make a change because he may be changing based on the lineup he expects to see. Ideally, you should try to exploit a weakness of his. That is my approach but there are smarter coaches out there that may have better ideas.