This model has two configurations which both use 8 20x4mm magnets and 3 to 5 small command strips.  Both configurations have 4 positions for knives.

The first configuration is stacks two 20x4 magnets in each slot.  This seems slightly stronger than the next configuration.

The second arranges the magnets side by side (vertically) instead to keep knives aligned better.  The strength still seems sufficient.

I suggest you test before gluing the magnets in to ensure proper direction. To glue them I simply used a small dab of hotglue under and above the magnets.

For the wall mount I suggest adding some super glue onto the 3d print side (a very small amount) before adhering the command strip to the 3d print to improve holding strength. Do NOT do this between the wall and command strip.

Please be safe using this. If you don't believe your magnets will hold the knives securely after testing please do not use it. 🙏

Note: It is beneficial to add something thin and grippy such as Non-Abrasive Grip Tape Strips to the knife facing surface to prevent knives from sliding down as 3d printed plastic is pretty slippery.

I have tested grip tape with both models and found similar effectiveness for either type.  I feel pretty safe with that change myself.