Hi - read up all month and just started slowly with low risk loans, high credit scores, low inquiries, 36mo loans etc but finding that the first loans to fill up are lower grade.
Many A rated loans have low buy in - I am sure people are looking for high ROI and higher risk but do these A grades get funded?
Also - for conservative account - best filter advice appreciated. 
A grade loans are popular with institutions, investors who consider consumer lending as another asset class, and investors interested in steady cash flow. Such investors are focused on diversifying across asset class instead of maximizing return within a class and on predictable income. Most A grade loans that are not fully funded earlier usually get filled at or near expiration.
To find appropriate filter, you may want to look at shared filters (Peer Filter) on PeerCube
http://www.peercube.com (Disclaimer: I operate the site). There are currently 15 Peer Filters that you can choose as starting point. As a conservative investor myself, I and, by proxy PeerCube, is conservatively biased. I don't consider anything that doesn't have a solid basis in theory, supporting research, and in historical data to backup any claims.