[kq76]

Well, what I envision happening is if you have a team that is built on the longball and have them face a deadball era team played under deadball era settings, the longball team's home run power is going to get nullified. And if they played in the modern era the deadball team would get crushed by the longball. I don't think that's "leveling the playing field" between the two teams like the OP seems to be asking about.

Leveling the playing field, I think, would be using the midpoint between the two eras, but I'm not sure that would work well either as then neither team would really be playing in the environment they were built to play in. Maybe what would be best is if you could have all games be played under the era of the home team and sure, the home team would have advantage, but for many series it might not come into play.