1 id dog
Just a couple of things I think I might share...
1. In your post you indicated that you were shooting an Optima... I am not sure that you will be able to get the SST with the supplied black sabot down your barrel, however Hornady is now offering what they call a "low drag" sabor with this bullet. It is an MMP HPH-3pEZ load colored red.... It should go down.
2. I have only shot the bullet at paper testing it's accuracy... It is accurate.
3. The only negatives that I have heard are at close ranges it, and its little brother the 250, can pencil its way through a deer and not achieve much expansion if only tissue is contacted.
4. There are a lot of positive reports also especially at the longer ranges.
5. Your chosen charge of 90 grains might also help the 300 work better @ shorter ranges because you are certainly not over-driving the bullet. Even if you went to the maximum allowed charge in a CVA, 100 grains loose, that should still be effective.
I beleive there are more effective bullets on the market than the SST/SW at a much more reasonable price, but then again I am another old man that fails to be impressed by high BC's in a muzzleloading bullet.
Hope some of this information helps your quest... gotta go huntin'