No matter what coordinate spread you put into the oparea file, the MB map always seems to start with a fairly narrow degree of angle for the map. Trying to put the coordinates of say the entire Hawaiian Islands or the Solomon Islands only results in that narrow degree view and then it's usually out in the ocean somewhere. When refining the coordinates to your preferences, just center up in the middle of where you want to go and then keep the coordinate spread down to a few degrees for accuracy.
Example:
ATO-West-Kiska Island, N52 30, E176 30, N50 30, E178 30
Of course once the oparea coordinates get you to where you want to go, you can expand or contract the view as needed.