I play the 50's too and 4 bet PF a bunch, sometimes light but mostly not quite so light.

Using the example you mentioned, you can 4 bet to say $30 and still fold your AK when it's pretty obvious old mr 17/12 over the road there has aces.

A lot of the time you're 4betting in these games you'll have AK. I hate putting 40BBs in preflop OOP with AK because when we're called we're missing the flop 2/3 of the time (more in fact, as his hand contains a larger than average number of Aces and Kings), and we have to decide between check/folding and getting all in with a maximum of 6 outs and often less. Neither of these appeal much to me.

With 100BBs I prefer to 4bet shove AK OOP, and to balance it I shove AA/KK and sometimes QQ too (against a light 3 bettor).

In position is another matter.

I see missing the flop with AK OOP as a con in these games unless you've decided to shove, and while that's possibly better than check/folding I'm not convinced it's a particularly good idea.