If it follows the White Rifle rule of thumb, the twist would have been 1-24 in the .50 caliber and 1-20 in the .45 caliber. These rifles are a real conical shooting pleasure.
I have shot sabots out of my White and discovered as you, they are very good sabot shooters. But when shooting sabots, I found mine likes to be "pushed." I don't know what you think on that. Other White shooters might comment on how hard they push sabots if they like. I'd be interested. But I sure like your post.
I like the action on that rifle.