1) Should I use "Share and Repost" or "Mass Track Repost"
a) MASS actions are when you use YOUR accounts to process a single item repeatedly. So all your accounts will repost your track URL.
b) Search and Repost, is where you search for many URLs and use a single account to repost those tracks. The hope is, the artist who has their track reposted, will check your profile out.
c) Share accounts reposting, is when you select multiple accounts to perform a search and repost action (b). This means, each account will repost a track in sequence and no two accounts will repost the same track. This means, across the accounts you can easily repost large numbers without any duplicate.
You want MASS REPOST
2) Should "Use Ac Creation Proxy" be checked or unchecked?
Checked. This will make SCM use the ACCOUNT CREATION PROXY that is assigned via the accounts details popup
3) Should "Allow Multi Acs Per Proxy" be unchecked?
This only applies if you are not using the account proxy
4) Should "Allow No Proxy" be unchecked?
If you are using account proxies, it doesn't matter
Those check boxes are quite old functionality and probably can be removed now. As when the app was first released you could get away with more on SC and didn't have to be so careful, plus the more advanced features and accounts tab didn't exist, so provided a way to control the proxy assignment easily.
Now, there are better was for controlling this. I hope to, next week, redo each tab and remove all advanced functionality to a popup tab, making the main tab more simple for novice users and adding more advanced features for more advanced users. Those check boxes will be coming off I think