Secret compartments in the sea chest

Due to the unusual thinking ahead that I have been practising, it has been fairly easy to plan and execute the interior of the chest.
In addition to the till and the two drawers, I have planned some secret compartments as well.

On this picture, the till and the vertical and horizontal dividers are in place. On the side (which is pointing upwards on this picture), a narrow 7 mm dado can be seen. this will accomodate a back for the small drawers. Behind this, the secret drawers will be located.

The vertical divider will be sliding in the dado on the underside of the till, and in a corresponding dado in the bottom. It will be secured by a small sliding key in both ends.
To access the secret drawers, you will have to remove the normal drawers completely, slide back the locking keys and pull the horizontal divider out. Then the two secret drawers can be removed, sideways compared to the normal drawers.

The secret drawers are intended to measure approximately 1" in the width, so they will be rather small.

If everyhing goes according to the plan, there will be 2 more secret compartmens. But they will perhaps be revealed later on.

I am using a hacksaw blade for sawing out the sides of the sliding key. I use it on the pull stroke.
The angle of my sliding key is 25 degrees. I decided that it looks fair, but apart from that, I have no idea if this is a traditional angle or not.

Here is a picture of the finished keyway (left), on the right side the experimental sliding key can be seen.
Much contrary to my normal behaviour, I decided to make a test before starting on the real thing.
The test keyway was made very fast, and the sliding key for it even faster. The surprising result was an immaculate fit. Just like what you would hope to see in the finished work.  Now I just hope that I can make as good a fit on the divider.