I use 28mm for cutting twisters using template as you can cut tight to the template with this. I use the 45mm for cutting blocks and for cutting strips I use my 60mm as it cuts up to 8 layers accurately its also better for cutting thicker fabric like denim. I use true cut rotary cutters as I like the handle and I have their big ruler 24 1/2in long. use what suits you best we are all different with different sizes hands and strengths.
