I've been interested in lever locks for the past month and I've read a fair bit of documentation on them,
Anyway, I spent my last week building a Hobbs hook for my lock (pictures below)

My lock, its key and the Hobbs

Full view of the hook

Detail on the tip of the tool
It's made of brass, soldered with tin, it's resistant enough to pick my lock i've tried pretty hard and it didn't brake.
The lock is a 4 lever Thirard lock, no anti-picking protection (obviously),
I've checked the hook can apply tension to the bolt while having access to the levers, so in theory my tool should be able to open the lock.
But I can't for the life of me manage to pick it,
I apply tention to the bolt then proceed to feel each lever, The second one is always the hardest to lift, so it should be the first one to lift, other levers are easy to lift and quickly come back in place when I stop lifting them, so I always try to work the second lever, but even when applying a good amount of tension no lever seem to "bind", so I cannot progress on picking the lock,
I was wondering if my problem was that I apply to little tension, because beside that I don't see what I'm doing wrong.
Thanks for reading and thanks to anyone who can come up with a good answer,
If you want more pictures, or picture from inside the lock, just ask.
If some of the vocabulary regarding lever locks is wrong, please tell me, I had a hard time finding the names of parts of the lock.