Old Ironsides being overflown by the Blue Angels
My understanding of Legion's vassal modules is that they require the player to use the physical charts that come with the game when using the vassal module...
(I know this because I made a vassal module for Legion games...)
I hope this helps.
I don't think that is true just for Legion Games. I can't think of a Vassal mod of a solo game in print that includes charts.
The problem with vassal mods for solo games is if you put everything in it then you have essentially given the game away for free. While the same can be said of any game, publishers seem to be very reluctant to wrap up everything needed to play their solo titles in a vassal package.