I've created it to be as light and fast to print as I can make and to have as many openings as I can get (and still keep reasonable).

Sory for poor printing quality on my pictures, I didn't care to make it look good just to get it fast, so filament was not calibrated, printed to fast, to hot, probably with overflow and was wet… still strong enough for me to not be afraid it falling apart during normal use (like dropping full spools from 1m height on it).

The walls are only 1 mm thick so with 0.4 nozzle and Arachne wall generator there are just 2 wall lines most of the time, so 2 wall loops is just enough. Requires almost no infill, but I'm using 20% lighting anyway for those a few places where it's needed. Also adaptive layer height improves printing time. It's optimized to not generate long bridges, so absolutely no supports required.
On my bambu I printed 4 containers at once in 6 hours using about 190g of PETG.
However for a single Samla box you need 2 containers right and 2 left, so use mirror option in your slicer to get the second one, because I'm to lazy upload twice the same model with only such a change. However it can contain something about 225g of silica gel per container. It's nearly 1kg for whole box… I think it's to much, I'm going to use just 2 containers per box.

The lid is sliding, because I don't trust those pressing ones. In my print it fits very firm, but you might need some dimensional compensations (you'd better not change it on container). Lid is symmetrical both up-down and left-right, so no need to mirror them too. And the single funnel will fit also the mirrored containers.
Fits very well to corners of the box, the 2 of them at the same long border and they almost have no movement (except up) - on one picture you can see the box hold in pretty awkward position and nothing falls.

Has a lot opening so dries the air in the box quite quickly (from 40% to 8% in less than 12h in my best case with only 2 containers in the box)

I could do better. Probably container should widen on top about 3-5 mm, but I'm to lazy… It's good enough. Have fun remixing!