I use a Top-end Hozan C-371 chain tool in my home shop; however, I keep a Park CT-5 in each of my bike saddle bags. I have rarely had any trouble using this tool.
This tip is a good one and spot on:
But I'll add a tip. Once the chain is positioned in the tool, the pin is screwed onto the chain's rivet and it begins to move slightly. Then back off the tool's pin and restart the screwing in. What this does is let the tool's pin better center on the chain's rivet before plunging into the chain's holes.
Another tip is make sure the pin on the tool is straight to start with and go slowly and carefully until you are sure the pin is being driven out straight. A mistake some folks make is going too fast. Slow and steady is the way to go.
Working in shops years ago I figured that out by myself as do most mechanics. This tip is good for all chain tools btw.