Finally I went there and had a chance to play with this safe again. I went there with a completely different approach. The first time I underestimated the job.
This time I was better prepared in terms of:
LIGHT
There was a light in the room, but was far and not bright. I brought a portable light and this made a huge difference.
HEIGHT
I was sitting on a chair but the dial was higher than usual, so I had it too close to my face and had to work with my arms higher than usual. I brought a small ladder and a cushion to sit on, so I could be at the correct height to see the dial and comfortable with my arms.
HEAR
The small audio amplifier I bought worked very well for me to hear all the lock movements and contact points. Having something else, other than the touch to feel the contact points is very important with these old and big safe doors. The spindle is so long and the lock so far, that it's not easy as it is on my workbench. Hearing them really helped.
PRECISION
Knowing that this lock didn't forgive small mistakes, I was ready to be very precise and scrupulous. I took note of both contact points and was ready for a long job. Last time I thought it could have been a couple hours maximum. This time I was ready to work all day.

Thanks to the help of all of you, I had a plan. 11 42,5 AL.

But first of all, I verified the info I had. I studied carefully the only thing I was sure about: wheel #2 or #3 was 42,5. And there was a low area around 10 on wheel #1. So I decided to double check that area and see if there was a better place to park wheel #1. There wasn't, wheel #1 was covered by #2 or #3 at 42,5. Using 11 was a good plan.
So I double checked the gate center on wheels #2 and #3. It was 42,5 indeed.
I also made a few high-low test to see if, with the new conditions, I could get better results. I did!
Wheel #3 was still the better choice for that gate. Unexpected but good.

It was time to start getting new info, and I followed my usual strategy: test more wheels together. Worst case scenario I waste half an hour. Best case scenario I get another gate. Comparing this graph to the similar one I made last time, clearly shows how different it is to get good readings in good general conditions.
As you can see, I got a perfect gate signature at 96. I was doing high-low tests but stopped writing down the results.
Trying to convert the dialing direction, with great surprise, I found nothing between 98 and 93 going Right.
This lock was going the wrong direction. I decided to brute force wheel #2 going Left... so dialed R L R L and then oscillated the dial on contact area until it was OPEN!
After opening the lock, I did not open the door so couldn't see what lock was inside.
I also won't reveal the last number, just to be on the SAFE side.
Thank you again for the help and support on this difficult job!
Cheers
