I like using it for heavy lead like 10-12.5mm in a 24-18 taper, but I prefer the thinner gzk In a wider taper for 3/8 steel and the likes as I feel it is faster relative to the draw weight. It still gets the job done though, I find a taper of 18-12mm is best for 3/8 (9.5mm steel)
Personally I prefer the 0.72 or 0.76 gzk for 8-9mm steel. 18-12mm for 8mm steel and 23-18mm for 9mm. You could shoot 9mm with the 1mm gzk, but I think it might be too heavy for 8mm, you might get hand slap if you're shooting ott.