3
Both! They are not mutually exclusive methods; they complement each other. Study your own life, looking at the solar returns within which the most important events/milestones/changes happened and also look at which progressions were active back then. If you can, look at the precession-corrected solar returns too (provided you're using the tropical zodiac); in my experience both make sense and each is an incomplete panorama of the year without the other.

4
I've found progressions to significate..a natural progression of events, a development of current life themes, while solar returns often indicate specific one-off events.
silvia

5
For a Year ? Or for an over all Picture ?

I think Secondary Progression, 1 day a Year, are very very powerful, but you need to go right back to your early Years and work thru it.

It can be a long long process, but progressed planets to natal planet Locations, Sign changes and House changes, and Angle changes, can be really really Eye Opening.

For me Secondary Progression is where it is at.

H