Andrew, it looks like things are moving forward nicely.
I have a few ideas that I'm sure, with your background, you've already thought of, but, just in case you hadn't, I thought it wouldn't hurt to mention them.
Donuts are generally cake flour. 22 kg of cake flour is an entirely different ball game than 22 kg of high-ish gluten flour when it comes to stress on the mixer. Mo gluten mo problems
As I'm sure you're aware, the absolute best substitute for pork in traditional Italian American sausage is veal. In fact, I think you'd probably find quite a few old school Italians who think veal is better than pork. I don't know what your availability might be for veal, or if it's feasible from a cost perspective, but, if you can get veal, that's what I'd go with.
The flavor in meat comes entirely from the fat. When blindfolded, it's virtually impossible to detect the difference between very lean beef, very lean pork and very lean chicken. They've done studies on this. I don't think the flavor of beef belongs in traditional Italian sausage, but, you could probably capitalize on the lean flavorless phenomenon by using very lean beef and combining it with either the fat from another animal, or, possibly even a hard vegetable fat, such as palm oil. Butter might even be neutral enough to work.
Regarding the recipe, anise is very fennel-like, so it probably wouldn't be bad in Italian sausage, but, if you're looking for that old fashioned NY area flavor, I'd probably skip it, as no commercial Italian sausage I've ever heard of contains anise. And you really want to be careful with the other spices. I've researched Italian sausage recipes online and they can get pretty egregious with the number of ingredients. Commercial sausage should be very simple. Fennel, pepper, salt, sugar- and not much more. I'm still trying to decide whether or not coriander should be a component, but, beyond that, I'd avoid it.
Unless, of course, a classic NY area commercial sausage is not your goal, and you're just doing your own thing.
When it comes to pushing an oven to do faster bakes, the thermostat mod is only one in a list of tweaks that typically need to be performed, and, when done on it's own, rarely provides much of a bake time reduction. As Walter pointed out, as you push the thermostat higher, the propensity is for the oven to burn the bottom of the pie before the top is done. Depending on how the oven is setup, you most likely won't even get balanced bakes at 590.
Balance (typically more top heat in an average gas deck when pushed to higher temps) is directly correlated to the number of BTUs the burner is pumping out and the manner in which the heat is deflected away from the bottom stone and up towards the ceiling. I don't want to sound too pessimistic, but we've had numerous members source Asian ovens, and the specs/build quality have typically been pretty disappointing. Does your oven have a single burner or a burner for each deck?
What are your oven's internal dimensions? If you want faster, balanced bakes, which, from your Lombardi's experience, I'm sure you know make better pizza, you need a very intense, high BTU burner and good deflection- usually metal sheeting between the stone and burner that leads the heat up the side channels and away from the stones. A brick ceiling also goes a long way in bolstering top heat for better heat balance at elevated temps.