I’d like to know what the regular and heavy words refer to regarding springs.
Do these words refer to the thickness of the springs and/or the durability?
The heavy springs I’ve got from ACD unlimited seems to handle a tight spring tension well, but are more difficult to control.
2 regular springs have already broke on me after a month or so of use, including the previous Tama regular spring which broke prior and I’m guessing it’s because I’ve set the spring tension too high.
Some sort of explanation would be appreciated.

Heavier springs offer more tension at the same stretch amount. If you were to try and stretch the regular and heavy spring by 1cm, it would be significantly harder to stretch the heavy spring.

So if you constantly find yourself maxing out the tension adjustment with regular springs, moving up to the heavy spring might mean that you are able to have the spring tension adjustment not as maxed out, or that you can get an even tighter feel than what is possible with the regular springs.

If you want other ways of increasing "tension", try using heavier beaters, setting them to hit the drum at a point higher from the floor, or changing your cam geometry to be heavier feeling (smaller circular cam for strap drives, shorter cam throw for Direct drive).

Even after experimenting with loose tension, the springs are still breaking. I am using the ACD spring geometry upgrades with Tama Speed Cobra pedals which originally have a different length of spring than the ACD springs designed for the Darwin and Phantom pedals. So now to get some of the sized springs for the Tamas and more experimenting. Thank you for the explanation.

Where does the spring breack ?