The biggest issue with lead is speed - drive it fast enough and it smears or gets enough friction to start softening more or whatever, causing accuracy issues and being a PITA to clean. Using the sabot alleviates that. I don't think you need to worry about it spinning itself apart (as some really light 45gr bullets at 4000fps can do from a 220 swift and similar with a faster twist rate, they never make it to the 100 yard line...) since it is one hunk of lead, especially if you are using a "hard cast" alloy instead of pure lead.
As far as accuracy, etc goes - the only way to find out is to get some range time in and try it. I know my .54 percussion didn't shoot 230gr .451 pistol bullets in sabots very well across several different powder charges, even though the weight of the bullet is really close to a .54 (well .530 ...) round ball in weight (224gr IIRC) and I'm not in the mood/position to spend a chunk of my minimal fun money allowance on finding out, especially since .54 maxis shoot as well as I can manage with the irons on the gun....
For terminal ballistics on an animal though I'd want to either stay with a proven performer solid, monolithic, or just high quality jacketed bullet. Or use a full bore diameter heavy bullet and reduce velocities.