Lets say you have a pre flop and flop maniac to your left. He is willing to go many bets pre with all sorts of trash. He will go many bets HU on the flop with any sort of draw or pair. I think HU he will bet the turn but I have seen him cap and then check the turn MW. He chills out significantly on the turn and river.

Pre flop

How many bets do you go with assuming it's hu with no cap.

KK
AK
TT
AJs

Post flop

How many bets do you go with A8, AK

on a 6cAs9s board?

How about 77 on

2s5s6c board?

If we had a read that he liked to take free cards on the turn would this change the amounts of bets?

How many bets is many bets preflop? And what are the situations like when he does go “many bets” with trash? AK and Aces seem strong enough to go all in with. AJs and Tens are probably also fine depending on how strong the read is.

Idk I would be gambling a lot with a player like this pre and on the flop. I don’t understand why his turn play would be so different.

With trash he seemed to bet the flop and the turn. He was making super thin bets on the river. I called him down several times with Ace high and he got me every time with a small pair. He was more value oriented than bluffy. Maybe he was just running well. I probably pay these guys off more than I should.

I've seen lots of pre flop and flop maniacs who then play more straight forward and passive on the big streets.

To answer this question properly it matters a lot whether you want to play a quasi optimal GTO strategy (i.e., to be nearly unexploitable), or play exploitatively. Maybe you can deviate from GTO selectively against specific opponents as in the case you describe, but this will raise other issues, such as other good players making adjustments against you. But in any case, none of the hands you described are worthy of an "all in" preflop unless the opponent is truly a mentally impaired douchebag on a suicide mission (assuming you both have racks of chips). Since in LHE the bets go in one at a time, at some point only AA should be willing to continue to rereaise. This is a big difference from NL where many different hands, for many different reasons, can be shoved all in preflop. Also, it matters a lot what positions you and your opponent are in. Is it UTG and UTG+1, or SB vs BB? These things matter when deciding on how many bets go in, both pre and post flop. Yeah, I get it that its always a good idea to get as many chips in as possible when you are an equity favorite (as long as both you and your opponent have unlimited bankrolls and you both will reload when you bust) and by doing so won't cause any future strategy adjustments by a poor playing opponent. But generally, limit holdem is a game about grinding down the fish, not trying to stack them in one hand.

Here's another way to think about it.

Let's say you went to the casino with $1000 to play $20/$40 limit holdem. The table you sat down at was a great game, with the idiot you described above on your direct left. You only have a $1000 to play with, so if you lose it, you have to go home. Would you rather..

A. On your first hand, go all in preflop with your AdKc vs the agrotard on your left after he shows you his JsTs, calls you a pussy and says he wants to flip for stacks

or

B. Grind it out for 8 hours and make your hourly (assuming you are the best player in a great game, and your time is not worth anything outside this game)

On the first part, I assume we are thinking of different types of people. If someone is a true drooler who wants to LOL gambol with 75 offsuit because it’s his favorite hand, I’m taking that every time.

As for the second scenario you presented, going to the casino with only 1k to play 20/40 is a terrible idea.