Rather than calling it light 3betting id rather say 3betting a polar range and you want to use a polar range vs villains you have fold
equity against.So you might 3bet a polar range against an utg opener with say KK+,A5s-A2s,KTs.Where as against someone who doesn't like to fold to 3bets you would use a linear range say JJ+,AQs+,AKo.
Then vs the regs who will be the Tag's and Lag's you have a mixed strategy combining the two previous ranges JJ+,AQs+,A5s-A2s,KTs,AKo, as we expect to have fold equity vs these villains but we dont expect them to be overfolding. You can look to 3bet KK+ and the
bluff part of the range A5s-A2s,KTs wherever possible.And play a mixed strategy with the rest of the range with either 3bets or calls.
To work out a polar range just multiply your value range by 1.5 to give you the bluff ratio so KK+ for example for 12 combos would give 18 bluff combos.The linear range is just pure value hands which can widen more and more the fishier the villain.