I was going to entitle this post
"Which day is best for launch day?"
However, I already know the answer: Tuesday!
It seems everyone wants a Tuesday because it allows a bit of a pre-launch and then you generally have the rest of the weekend to continue to make sales before the weekend kills the launch dead in the water.
If someone has a Tuesday, then you typically need to leave 2 days before you can launch in the same week on a Thursday. However, personally I'm not too keen on Thursdays as they generally fizzle out a lot quicker with the dreaded weekend only 2 days away.
Therefore, if you want to fit 2 launches in the same week (and I mean 2 launches where the product owners will have similar JV partners on board) then one tactic is to have one launch on a Monday and the other on a Wednesday.
Its all about who (which JV partners) you can get to commit to your launch and then somehow plan it so that they arent promoting something round about the same time. i.e. marking your territory.