I make my own too, based on this recipe:
https://www.theguardian.com/lifeandstyle/2013/aug/23/homemade-pork-scratchings-picnic-family
The spices vary, depending on what I fancy, but in my world a couple of things make a difference. Firstly, ensure the uncooked rind is dry before cooking. I order to be sure of this, I bring the rind out of the fridge and leave it uncovered for about an hour, before cooking. I tend to put it in the empty, unseated grill, and close the door, rather than it sit on the worktop.
Secondly, if the rind is tough to cut into whatever shape you're going for, it's super easy to cut once warmed, so I take the single piece of rind out of the oven after 5-10 minutes, then it cuts like butter.
I actually use a cooling rack, sitting in a shallow tray to maximise heat circulation, but prevent the pieces falling between the slats of the baking tray as the crackling curls.
If you don't want to season your crackling pre-coking, immediately after cooking, you can put some seasoning in a poly bag, add the cooked crackling and shake to coat the pieces. Be careful though, as the crackling is very hot at that point.
Enjoy!!