Lots of folks use that formula for a hunting slug and I was going to say "go for it"...then I re-read you original post and seen the 2000 fps thingy...I suspect with that soft of a lead formula you will get barrel leading at that velocity unless you do some of the latest fad to hit the cast bullet scene and that is to powder coat them.
Conventionally wax lubed 50-50 slugs do work very well under 1400 fps but above that rifling twist rates will be a factor in both leading & accuracy (I don't know what the twist is for a 9.3 but suspect it is fast enough to try to "tear" the lead ).
Powder coat is more than a fad. It is solution to a number of challenges cast bullet shooters face.
I am shooting the NOE285 Grain gas check bullet powder coate at 2000 fps (imr4064)with no signs of leading and a 2" group.
My seating die stays clean. - that is the nicest benefit.
My alloy is is 8 lb wheel weigt, mixed with 2 lb pure lead, and 1/4 lb tin.
no signs of leading, accuracy matches 285 grain Privy Partisan bullets.
This is a softer alloy than pure wheel weights and pure wheel weights do not expand even deform at 1400 fps on soft tissue.
With cast bullets shot placement counts.
Also as you increase the percentage of lead in the bulley you may be decreasing your maximum accurate velocity.
In my experience of huniting with a 303 ross and 314299 180 grain bullets I have never needed a second shot on Mule deer. Bullet placement counts.
You may have to choose a lead alloy that you are happy with the expansion and work up a load that allows good accuracy with that alloy. and you may not be able to reach 2000 feet per second with a bullet that expands well at lower velocities.
All of the tricks that allow increased velocity with cast bullets also make for a harder bullet with less potenial to expand.
That being said the lenght of the 285 bullet that rides in the rifling may allow higher velocities with softer bullets. Also the 0.366 diameter of a flat point 285 grain bullet will impart a great deal of energy to a game animal on a well placed shot.