Static and dynamic sag are just part of the nomenclature of suspension and simply puts everyone on the same page. Whether or not a fully loaded bike is dynamic is beside the point, it just gives that parameter a name.
Static sag is relevant in so much as the relationship to the dynamic sag will tell you a lot about the spring rate.
Get the static sag set at say 10mm and then load it and it goes to 50mm. That will tell you the springs are too soft.
In my case the static sag is alarmingly high, but then only deflects a few mm more when loaded. That tells me that my springs are way too hard and I'm using enormous static sag (and rebound damping) to stop it topping out . Even though it's working relatively low in it's stroke it never bottoms out, confirming the former hypothesis.
Fortunately the damping is rather good, so deals with the limited travel.
It actually handles fine, but the springs and set up are something I will look at next Winter.. Nearly did it last Winter, but bottled out!
Looking forward to joining the esoteric tuned suspension crowd..