There's a forum post suggesting map pins for blueprint alignment.

I think that if you added a 'map pin' 1x1 entity (or rail-aligned 2x2, to support rail blueprints?), that when placed, set the global offset based on its location, that might be a useful addition to the mod, as at the moment, setting offsets currently requires setting values and trying until you get values that work.

It might make sense to have something similar for creating blueprints; a set of 'map pin' entities that you can use (similar to how Recursive Blueprints uses wooden chests) to specify the various offsets by placing ghosts in-game, in addition to editing numeric offsets in the GUI.

Edit: I'll eventually learn which way the brackets go for URLs in MD.