How to use Timing Tells to make Light Calls in 4Bet Pots

My opponent in this hand is a regular who appears to be a little aggressive. We have played some at other tables but have not had any major confrontations yet.

Poker Stars $0.25/$0.50 No Limit Hold'em - 9 players
Hero (CO): $58.55
BTN: $50.00
SB: $49.50
BB: $19.79
UTG: $50.00
UTG+1: $72.96
UTG+2: $20.00
MP1: $102.30
MP2: $50.00

Pre Flop: ($0.75) Hero is CO with A 4

5 folds,
Hero raises to $1,
BTN raises to $3 (7s),

Because of my Ace blocker and my opponent’s hesitation before his 3bet, I decide to put in a 4bet bluff. 

2 folds,
Hero raises to $6.75,
BTN calls $3.75

Flop: ($14.25) 5 6 4 (2 players)

After he decides to call I feel his range is pretty wide, so I decide to check to him and let his timing narrow his range down for me. I also have a fairly strong hand for this board as the over cards in his range missed.

Hero checks,
BTN bets $5.50 (5s),

There is nothing too significant about this timing, but since I can definitely have the best hand and have plenty of turns that can help me, I will happily call this bet. 

Hero calls $5.50

Turn: ($25.25) Q (2 players)

Hero checks,
BTN bets $14.50 (3.5s),

Now this quick timing is exactly what I was hoping for. If this card helped my opponent, or he already had a strong hand, he would have taken longer to make this turn bet. With any strong hand, he would have had to at least consider his bet sizing since the stack to pot ratio is getting a little awkward.

Hero calls $14.50

Given this read, I am calling with the intention to call any river bet, unless the combination of the river card and his timing change my mind. 

River: ($54.25) 8 (2 players)

Hero checks,
BTN bets $23.25 all in (2.21s),

This timing is absolutely perfect, as he had to of decided on the turn that he was going to bet almost any river in order to bet that fast. Any strong hand that wants value would never be considering something like this on the turn, as they would wait to see what the river card is before they want to act.

Hero calls $23.25

Final Pot: $100.75
Hero shows A 4 (a pair of Fours)
BTN shows T A (high card Ace)
Hero wins $98.25
(Rake: $2.50)

Always remember that whenever a players bets fast on a street as if they do not care what the card is, their hand is not likely to be very strong. The next time you have a big hand, watch your own timing on all three streets to see the hesitation you naturally make. Feel free to post any questions or comments and good luck!