I am looking into purchasing a flintlock for the first time. I am a lefty and know that I am limited to the rifles I can buy. I am looking at the Lyman line of guns. The3 available are the:

Great Plains Rifle .50 cal
32" barrel
1 in 60" twist

Great Plains Hunter .50 cal
? barrel length
1 in 32" twist

Deerstalker .50 cal
24" barrel
1 in 48" twist

Why the difference in the length of the barrels? What kind of twist do I need toshoot sabots? The Deerstalker is about 100 dollars cheaper than the other 2, but I'd rather spend the extra if it is going to perform better.
Is there any other southpaw manufacturers out there?
Any info and opinions is greatly appreciated.

Thanks