Q: How do I create a league with my favorite players from baseball history?

A: Baseball Mogul already has a feature that does something like this, called "All-Time All-Stars". To create a league with the best players from each of the 30 major league franchises:

1) Run Baseball Mogul.
2) Click "Start a New Game of Baseball Mogul".
3) Click "Custom".
4) Click "All-Time All-Stars".

This will create a baseball universe with 30 teams, each populated with the franchise's best players (at the beginning of their best season).

Q: But I want to choose the players in the league.

A: Baseball Mogul has multiple ways to do this. But the easiest is probably to edit the text file that is used by the "All-Time All-Stars" feature.

1) From the Baseball Mogul Help Menu, choose "Open Baseball Mogul Folder".
2) Go into the "Input" folder and then into the "Players" folder.
3) Open "All-Time All-Stars.csv". (Recommended: Make a backup copy first)
4) Delete the rows for any players you don't want to include.
5) Add rows for any players you want to add. You will need to know the player's "Register ID":

You can find this by visiting the player's Baseball-Reference page and clicking on "Minor Lg Stats" — the player's ID can be found in the URL. 

4) Delete the rows for any players you don't want to include.
5) Add rows for any players you want to add.​

For Step 5 above, you will need to know the player's 12-character "Register ID". You can find this by visiting the player's Baseball-Reference page and clicking on "Minor Lg Stats" — the player's ID can be found in the URL:​

Alternatively, you can download the Player Register from the Baseball Databank (this file is also found in Baseball Mogul's "Database" folder).

​The player's "Register ID" is in the column labeled "key_bbref_minors":

6) Save "All-Time All-Stars".
7) Start a new game using the "All-Time All-Stars" option.

Q: Also, I only want to include players from the 16 pre-expansion teams.

A: Follow the steps above to select your favorite players from each franchise. For post-expansion teams like the Arizona Diamondbacks (ARI), leave that part of the file as is. After you start a new game, you can go to the League Editor and delete the teams you don't want included. This will also delete the players on those teams.

"Chris V." recently wrote the following review for Baseball Mogul 2019:

My biggest complaint is the historical rosters having players you’ve never heard of having all these high ratings. For example, I just started a 1989 season for the Dodgers and there is a catcher named Homar Rojas. His ratings in commish mode are as follows: contact 77, power 81, gap power 90, eye 69, speed 67, arm 89, range 77, fielding 66, bunting 80, health 83. There are many more examples like that. It almost feels like the programmers are sneaking their names in here and making themselves really good. Make them save that for their own create a player game.

That ruins the game for me so for that, I give 2 stars.

Previous versions of Baseball Mogul had a problem with extreme outliers. Babe Ruth is the best example. Baseball Mogul’s rating system assumes that player performance almost always falls within about 4 standard deviations of the league average: this should cover 99.994% of all players.
​
Unfortunately, Babe Ruth hit home runs at a rate that was 4-6 standard deviations above the rest of the league. In a simulation that produces a realistic distribution of outcomes, the chance of a result that is 6 deviations above average is about 1 in a billion (1,013,594,692 to be exact).

Yes. You probably already know that you can resize the main window as you can with most other apps in Windows, by clicking the minimize and maximize buttons in the upper right, or by grabbing the lower-left corner and dragging it until the window is your desired size.

However, I assume you're asking about the dialog boxes (aka "popup windows") such as the Lineup, Defense, Bullpen, Sortable Stats, etc. To change the size of dialog boxes, go to Options on the Tools Menu and change the setting for "Dialog Box Size":