The carabiner is Very small and lightweight - 1 1/2", maybe 2" long? I think it's actually smaller than the scissor clips I use. And yes, I can put that on a regular lead for a minimal extra fee.
My standard scissor clips are probably 2 1/2" to 3" long, but also lightweight.
I always hated the banging of front clip harnesses, too - part of the reason I stopped using them. That, and they didn't work for Inara.
You might want to try clipping the leash to the front ring, but then running the leash under that front strap. Still works like a front clip harness but no banging.
Or buy one of my leashes. They're magic and fix all woes.