Ok, let me say that I think the idea in general is great. It could be very interesting to play.
It's also certainly feasable to do. There is no technical reason that we couldn't update your mod every week with whatever changes you want.
The only problem is the time factor. It's not "hard" to make changes to the PBW server, but it does take some time. Which we don't all have an abundance of.
What I would like to suggest, without being a wet blanket on the whole idea, is that you put the game on PBW to handle the turn receiving and distrobution, and set it to "No Automatic Turns", and then download and run the turn files off line on your own pc.
I can tell you from my own experience I ran a couple ver 1.35 games this way and it was not really difficult once I did a few turns and became comfortable with the process. And I also ran PBEM games the old fashioned way and PBW, even with processing the turns offline, is way easier.
You don't have to worry about lost files. If they don't get the game file they can just download it again. They get instant confirmation that there turn has been submitted. And you can have the turn timer will still send reminders if they are the getting close to the limit, or if they are one of the Last players to upload.
And this way you have no limit to the nubmer of changes to you mod. You could change it after every turn if you want.
And this even has one small advantage over regular PBW games. If someone submits the wrong turn or it gets garbled in transmission, the host will get an error and can notify the player and have them send a new turn.
And your friendly neigborhood PBW admin team doesn't get run so hard. (My favorite part.

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Geoschmo
PBW Admin Team