This thread here:
http://www.ootpdevelopments.com/boar...ad.php?t=63976
goes into how to adjust a csv schedule file to match real calendars. Basically you can use a spreadsheet to adjust the day numbers. One problem is that if you do that on the same basis file you'll may get bored with having the same teams play in the exact same order every year. On the other hand if you tried to do it by exporting the schedule after rolling over to the next season (during which the game automatically mixes up matchups by juggling the teams within division) the process is made a little more difficult by the comment lines in the exported file.
An alternative is, while the game randomizes the matchups as it does, to just maintain the same calendar each year. I'd figure most people do this. It works fine with the only shortcoming being that if the first season begins Monday April 5, then every season begins Monday April 5, even though that date falls on Monday much less often than every year.
The Stickware schedule generator does tell you the proper info needed to have the dates in the game fall on the days of the week they really did/would. Frankly, though I personally always aim to make it correct, I am willing to cut this corner if most everyone else does. Le Grande Orange would agree you though - his motto is that "proper schedules matter." I meanwhile am more apt to follow "decent schedules are good enough." Presumably LGO will reply here also (we tend to run in the same circles) as I think he has been hoping along the same lines and has thought this through as you have.