best options on 7z for smaller size

[ddim1306]

I need to know which options i have to set when i am creating a 7z archive for getting a smaller size
for example i dont know when i have to choose
1.what compression method
2. solid or not
3. dictionary size

Please if you can just explain to me the basics of each option and write to me the best one for the above purpose.
thanks

 

[getochkn]

Size between the best and slowest compression and the fastest isn't really even noticable. Maybe a few MB on a GB sized file. Not really worth the extra time it takes.

 

[ddim1306]

anyone who can answer my question?