It sounds like you can apply some pressure on the flop. If he's cbetting 50% of flops and his stronger hands are not a part of that, he really has to be bet/calling hands like A hi, overcards and bottom pair to give himself a chance to do OK against an aggressive check raiser. So start pushing him around when he cbets the flop if he's following the strategy you talk about.I think your passive strategy with strong hands is probably correct. If he's checking back a lot of air and strong hands and cbetting 62% of the time, that looks like it should reasonably contain some bluffs that you can maximize your value by allowing to fire that turn bet (and perhaps a river bet at times, though that isn't apparent to me with the information provided).You can also play a few more speculative hands than you normally would against an opponent in a similar situation. This is because this opponent checks back a lot of strong hands, allowing you to see turns a higher % of the time. Also, when he cbets, you are facing a weaker range, so your speculative hand does better here (calling faces a turn double barrel a lower % of the time and check raising has more fold equity).That's what stuck out to me when reading your description, I'd start there and pay attention to how he adjusts (if at all) and any other valuable information he gives about his hand makeup. Keep in mind if he's showing up with very specific hands or repetitive hands it could be a sign of some selectivity (variance). Kind of like if you get all in preflop 4 out of the first 20 hands and each time you see KK or AA, you wouldn't consider your opponent a maniac or even loose 3bettor (it's a bit more complex than that but this would be a basic example).