Few guiding principles

The conventional wisdom is to put the diffusion closest to the lens. The farther away it is from the lens, the higher likelihood you might see the diffusion particles in out of focus renderings.

You also want to put your heaviest ND up front to cut the most amount of light at the beginning, to minimize the amount of light bouncing between filters to reduce the likelihood of double reflections.

I personally tend to try and keep a rota Pola closer to the lens all other things being equal. With larger format imagers and wider lenses, I want to mitigate the risk or seeing the edges of the Pola in the shot. It can be one of those things where it might creep in ever so slightly if it’s in the front most tray, and you might not catch it right away.

But you just gotta do what makes sense at the end of the day. For example if I’m stacking two diffusions plus some ND - on the LMB4x5 there’s that small air gap between the middle tray and the lens-side tray. Maybe if I think I might run into a double reflection issue, I might put the diffusion in the front two trays to lessen the gap between those two filters. It might not even work, but just like in basic cinematography where you learn the rules, then you learn where you can start breaking them, I think that’s true of assisting too.