There is always a clear choice. It might a matter of experience and "horse sense and a cool head and a keen eye" (with apologies to Meredith Wilson) but there is always an advantage to one or the udder.
Lou Figueroa
ya got trouble
I'm with Lou on this one. There is always a reason that one group is better than the other. If I'm looking over a spread that presents no trouble balls, i.e. both groups in the clear,I then start to compare the patterns themselves. One group will almost always lay better than the other.
When I compare patterns,I start at the eight ball and work backwards. Find possible key balls, then look for clusters. It will become apparent which group should be played. It's very rare to find a table where both groups are exactly the same.