Hi Jake,
If your dives are 1:30 with 1 min comfort and 30 seconds "gotta breathe" harsh contractions, try changing the way you're breathing to change the time contractions start to be closer to halfway through the dive or sooner. Contractions should start earlier and easier and give you a greater margin. Your max times will probably decrease at first but then improve and the contractions will become a cool part of the dive and a marker to start making your way back rather than a rush for air later than halfway through the dive.
Everyone is different but this is what works, and didn't work, for me.
The first thing I did when I started freediving last summer was overbreathe, big inhales and long forced exhales or just one purge which was wrong wrong wrong, my contractions started really late and like a bomb, making holding my breath through them almost impossible. It was like I was fighting the contractions, and couldn't win.
I realized that for me this was a way I didn't want to go so started trying different ways of breathing to have contractions no later than halfway through each hold/dive.
I try different things dry static before trying them in the water, always checking the times contractions start, for example, 1:30 comfort, another 2 mins + contractions. The first say 15-25 seconds are a little uncomfortable, followed by a long comfort zone with contractions, then the squeeze. Lately I've been trying to feel the contractions as more of a smooth wave flowing through my body and less of a hiccup in my guts. In the water the contractions are even cooler than dry.
First thing I concentrated on training was the right way to breathe for my body to have contractions half way through the hold. This meant just breathing normally, no purging/forced exhale, just one deep inhale before hold and pretty soon my contractions were kicking in soft and halfway through the hold. Encourage your contractions to start early. Sometimes swallowing or hiccuping with your diaphragm can start them off. Much later when your contractions are a normal part of the hold you can start resisting them. Don't get into the habit of swallowing.
Second thing I concentrated on was getting comfy with contractions in the water. I did this with my buddy watching from above, neutral at 10m, dive to 5-6m so positively buoyant, hold a rock to stay on bottom and chill, and again pretty soon contractions became a normal part of every dive.
All through this I was not interested in max times, the goal is to find a breathing style that works for you so contractions start at the latest halfway through the hold and to get comfy with them. The earlier they start, the better.
Then I started changing things in my breathing to get longer times, always making sure my contractions started at the latest halfway through the hold.
3/4 heartbeats in 6/8 heartbeats out for recovery time is to relax relax relax, check all your muscles especially up top, neck-shoulders, no tension anywhere. Just breathe with the diaphragm (bottom front back and side of stomach/ribs) and not the upper part of your chest. The upper body produces lots more tension.
Dry static tables a few times a week are a great way to train contractions and check what is happening with your body with different (even minor) changes to your breathing.
Apena stretching is a great way to train relaxation while breath holding, you can do this every day.
Read this back to yourself
how to push past contractions?
something I really need to push past
You're thinking of contractions as something negative, something you HAVE to PUSH PAST, or fight against.
Reset that thinking, forget about max times or depths, forget about fancy breathing techniques, breath normal, relax, train and enjoy your contractions, it's your body using it's air more efficiently.
Remember, contractions are your friend.