Larger hole cutters will require more pressure than the smaller ones -- sometimes a lot more, depending on the size. This is why we don't offer very large cutters.
To increase the pressure applied when cutting holes -
- with a table press: Place the press on a surface low enough that you can fully straighten your elbow when pressing down. This will maximize leverage and allow you to lean your body into the press to increase.
- with a handheld press: Rather than holding the pliers in your hand, rest the bottom on a table instead. Then, press down on the top handle of the pliers. You can use your other hand to help. This will provide better leverage so you'll be able to apply more pressure. Like this.
The hole cutting dies also work best with material that have some compression (ie. cushioning). It may be difficult to cut a large hole through something very flat and thin like a single layer of cotton.
Instead, place a scrap of plushy leather, vinyl, cutting mat or even several extra scrap layers of the thin fabric on the bottom die, under the layer you actually want to cut.