Recently I found myself with AK in early postion and raised to $12 only to have the CO (LAG) 3-bet to $45. All action folded back to me and I feel that if I just call here to see the flop the CO is going to either C-bet if I check and raise if I bet out due to the fact that he sees me as TAG. A call would basically mean I was hoping to hit a dream flop (1% of the time) and then let LAG destroy himself. But we all know dream flops are way too rare to hope for.

I feel the only option I would have here against this type of player is to 4-bet PF OOP in order to take control of the pot and thin out his range. The only way he would 5-bet in this situation is with AA KK and sometimes QQ so when he calls I could put him in the range of AX (which we dominate), QQ - 99 and possibly a crying call with just 2 face cards, maybe suited. If he does 5-bet its an easy laydown, and if he calls a C-Bet should end action unless the flop hits his range in which case its an easy b/f.

Is there anything else I missed? Range wise etc., also does this type of play usually work better against TAG or LAG?

Again I am seen as TAG so that allows me to steal more pots then warranted.

Stack sizes please...reads on player as well

I think you have a lots of good reflections OP when it comes to how to define a 4 bet range and implement it to your game.

What you should look for if you want to put in a 4 bet, is that actual villains 3 bet tendencies. If your up against a villain that 3 bets you regurarly and you have seen proof (actual hands showdowns) that he 3 bets you pretty light, you could go ahead and 4 bet AK for value against him. If i see opponents that 3 bets my opens with hands like AJ/AQ and 99-1010 for example, thats when i seek out creating a 4 bet range for myself against that opponent.

However, AK could be a fold instead if your early postion open gets 3 bet by a very tight player who 3 bet rarely preflop. In that case AK change into a RIO hand who can lose you ton of money.

I suggest you make sure of reading this concept of the month "relative hand strength" as i feel that topic fits great into this debate about when or if to 4 bet.