let say the album comes out late summer

[chiliD]

That depends on a few factors.

1) if the album is delayed, the tour COULD start BEFORE the release of the album.

Case in point, back when the Eagles released "Hotel California", the tour had already been in progress for about 3 months. (they played almost ALL of "Hotel California" during their set, nobody had heard the songs yet. Didn't go over all that well, until the album finally came out...then people started having "song recognition")

2) how the album does saleswise after its release (IF the tour hasn't already been booked beforehand)

Some artists' albums don't do as well "out of the gate" as anticipated, making it difficult to book the size venues they'd planned to play (or sell tickets to the shows that had already been booked)

In the case of the new Mac album, I'd say the tour will start (or tickets will go on sale) somewhere around a month to six weeks after the release of the album.