There isn't a maximum limit. Think in terms of patterns instead. Limit yourself to how many links you think you can keep building on a daily basis for a while. Different niche websites will attract different amounts of links. For one website it may be normal to suddenly get hundreds of new links while for another website it may be more natural to only get 10-20 links a day. If your links are from quality sources you should have nothing to worry about. Ensure that you do vary your link anchor text. Building lots of links with the same link anchor text will set off red flags.
If you are dependent on Google and its traffic - why worry about numbers of backlinks? Instead concentrate on few quality & relevant links/month than huge amount of links. Its not only th numbers of links for Google, but quality and relevancy too matters a lot. Make a long-term (min 6 months) plan and work accordingly. If I were you - I would have first improved quality of my site, try to attract some natural links and when the site gets a bit old - would have gone for conservative link-building campaign rather than link-building blitzkrieg.
and what denotes a quality source? PR or traffic or both? or something else? thanks you for your help!
I don't base link quality on PR or traffic. It is more about whether that website is spammy at all. Sometimes a PR0 is a sign that they have done something spammy and got penalized. In general higher PR websites do tend to be higher quality, but it is not always the case. Watch for things like very poor website design, overuse of keywords, a large number of reciprocal links, a large number of unrelated links, an excess of ads, etc. Basically you should avoid getting links on any websites that might get penalized for one reason or another. Too many links from spam websites might trigger some kind of red flag.
the quality link is the one that has same niche (content) to your website. Backlink from a high pr page AND same niche is the most important one.
ohhh, I see, I see. interesting. all things good to know! thank you, again... sorry to sound repetitive, but I'm truly grateful. new to all of this, really... forums are a great place to learn!