Asperius wrote...
I'm very confused about SP/MP relation. I have 6 sheps and which one will benefit from my MP playtime?
In a way I am glad US players will start playing ahead of us 3 days so they can give us usefull insight for our first run. I will use Matt Shepard import first to romance Steve. 
The best explanation I've seen for it was:
"
Readiness isn't points, it's a percentage. In the main game you have a thing called Total Military Strength which is the combined total of all your war assets. The percentage of that force that is ready to fight (which is calculated using your Readiness %) is called your Effective Military Strength.
Your Effective Military Strength is what you're going to use when you try to take back Earth. The higher it is, the better.
Promoting a character to single player turns them into a war asset worth 75 points that is tied to all the Shepard you have or will ever have. This stacks if you promote multiple characters. There's no AssBro or AssRev style micro-management where you assign your N7 operatives to complete tasks.
It is easier to get the best ending with a high Readiness score, so yes (though at the end of the day, it's the Effective Military Strength that matters). It's best to play multiplayer concurrently with your single player playthrough so that your Readiness remains high. "
Readiness as a percentage declines, but it's entirely possible to max it out (in terms of points) by doing singleplayer sidequests and finding war assets.
I'm sure there'll be a better explanation for it soon. Or at least, I'd hope so.
I'm not doubting much of what SAFG is saying, though. S/S Ashley and Kaidan seems pretty likely indeed.