Here's the way I figure it usually. The high E will require the least-if any intonation adjustment. In other words, the saddle location of the high E string is going to be nearly exactly double the distance of the 12th fret. (12th fret top is centered between the nut and the saddle) so because all bridges are different, I set the high E saddle to a place where I can still go a little forward, but its basically right near the front of the bridge. I set it visually. Then I position the bridge to the point where that high E fulcrum is exactly at scale length, and I mark that position, and drill for the studs so that the bridge will lie right there.
You're right that Schallers, OFR's and Edges are all different. They are pretty much interchangeable without moving the studs, because they all have enough range of motion in the saddles, but I like a visually centered group of saddles, and I believe the bridge performs its best when the saddles aren't too far forward or backward.