C-beting, check-calling or check-raising OOP with iniciative?

Hello.

I used to be a player that c-bet a lot, on FR with a tight opening range that was fine, but transitioning to 6-max that leak became more costly. I am trying to work on that aspect of my game among others, and would like to hear your opinions on 2 hands that I had iniciative OOP. Both hands are played on PokerStars.pt. Now i have a CBET_IP:87 and a CBET_OOP:45.

1st hand:
The oponent is a regular on the site with 24/18 and i guess he views me as regular as well. In this kind of hand before I used to c-bet, this time i decided to check-call, but i think that check-raising the flop was the best option, what do you think?

Poker Stars, $1/$2 No Limit Hold'em Cash, 3 Players

SB: $439.67 (219.8 bb)
Hero (BB): $248.72 (124.4 bb)
BTN: $322.22 (161.1 bb)

Preflop: Hero is BB with K♥: K♦:
BTN raises to $5, SB folds, Hero raises to $18, BTN calls $13

Flop: ($37) 8♥: 4♦: T♥: (2 players)
Hero checks, BTN bets $17.25, Hero calls $17.25

2nd hand:
The player on the BB is almost an unknown to me with only 24 hands played with him, the player on the BU is a regular. Here i opted to c-bet OOP because i was up against 2 players, but I am thinking wether that is a reason that justifies it, or wether i should go for check-raise flop anyway as if i was up against one player.
Then i check-raise the flop, i am wondering if that was the best line.

Poker Stars, $1/$2 No Limit Hold'em Cash, 5 Players

Hero (SB): $232.55 (116.3 bb)
BB: $203.70 (101.9 bb)
MP: $231.75 (115.9 bb)
CO: $46.29 (23.1 bb)
BTN: $200.70 (100.4 bb)

Preflop: Hero is SB with A♣: A♠:
2 folds, BTN raises to $4, Hero raises to $18, BB calls $16, BTN calls $14

Flop: ($54) 5♠: 7♣: 2♠: (3 players)
Hero bets $34, BB folds, BTN calls $34

Turn: ($122) 4♣: (2 players)
Hero checks, BTN bets $48, Hero raises to $180.55 and is all-in, BTN calls $100.70 and is all-in

Thank you very much for your opinions.