If you have not already done it, check out the list of the scenarios for the two titles you are trying to compare.
Just scroll down to the Squad Battles Section and select a title.
https://www.theblitz.club/scenarios/b-15.htm
You can read through the scenario descriptions, and determine the number of turns, size of the scenario, and even read what other PBEM players have to say about the scenarios, if they took the time to rate the scenario, after they played it.
Most scenarios listed will be stock (come with the game) however, there will be some 3rd part scenarios listed, too.