csi-tech,
Looks like you have done your homework, and you should have a great shooting rifle. You would never get 100% reliable ignition using 777 Pellets with the standard breech plug. I have 2 Sidekicks and a Huntsman, as well as 3 Whites, 6 Knights, and a T/C. The Huntsman is my favorite, but it sure didn't start out that way. I have modded just about everything on mine that I didn't like. The breech plug tool was first, then a Monte-Carlo stock, then the ramrod/jag, then the .25 ACP plug, then the sights, then the Hubbard breech plug, then the carrierless 209 breech plug. It is now my favorite, and is still batting a thousand in the Elk and deer woods.
As far as the Hornady SST and T/C Shockwave, they are both made by Hornady, and the standard bullets are the same except for the tip color. The SST's will have a red tip, the Shockwaves will have a yellow tip. The .45 caliber bullets for the .45/.50 caliber (black) sabots come in 250 gr, and 300 gr. They also have some bonded .45/.50 cal T/C Shockwaves in yellow sabots, and a .40/.50 cal Shockwaves in a blue sabot as well.
Sounds like you have 250 gr and 300 gr bullets to me.
Here is what the old 250 gr Shockwaves, and 300 gr SST's look like in sabots. These are old pictures, but the only real difference is that the newer versions have a slightly more rounded tip, and the SST's are now acually using the Flex-Tip (FTX) that is more like a hard rubber than polymer.
This should give you a general idea as to what you have. The ogive on the 250's will set below the petals on the sabot, and the ogive on the 300's will set up near the end of the petals.
250 gr Shockwaves in various sabots
300 gr SST's in various sabots