Doesn't SOM or APBA offer a component to stealing in their games with each runner able to try to "get the jump" on the pitcher? And if they do, their success rate is higher than if they don't get the jump but go anyway? I think baserunners like Brock, Henderson, Cobb get the jump a lot while Frank Howard/Johnny Mize types remain statues at first. To follow through with this idea, I believe when Cobb, Henderson, Brock in their best years "got the jump" on a pitcher, they were 90-98% safe at second base. They could still attempt to steal second without the jump, but their success rate would be lower, say 60-70%. Some guys who don't "get the jump" are not allowed to steal that time on base... until the next batter comes up... or they reach the next base. In this example, I'm figuring the catcher has an average arm.
The concept of a runner "getting the jump" is based on at least two factors I think - the ability of the pitcher to hold a runner close to the bag, and the proficiency of the base stealer - guys with 85% or better steal rates, and guys with 50/60+ stolen bases that season. I don't know how you go back in time though and assign hold rates for pitchers such as Matty or Walter Johnson. Maybe assign everyone the same rate before 1950 if the appropriate stats are not available and give the edge to left-handers by say 5% over righties. Food for thought. Keep up the excellent work. Can't wai8t for the new engine to come out.