There is no standard answer to that question because each individual has had difference experience with google concerning that. If you are doing it manually, less than 100 comments is a good idea. I really dont like blog commenting on a money site directly. Instead of that, I do linkpushing and use those other sites with automated blog commenting.
As many as you want. It will not hurt your site. I know a lot of people will probably disagree, but keep on commenting. I guarantee you it will do nothing but help.
I have been doing manual blog commenting on around 50 sites for last few months. effects have only been positive, more in some, less in some. but the problem comes when few of those high Pr blog comments get removed. so you have to constantly keep replenishing with fresh links.
There is no limits to blog comments, point your squidoo and hubpages dont point the main site directly. Do the Comments Manually.
Yes, getting the same number of backlinks every day is sooooooo natural Build as many backlinks as you can! Blast not only your homepage but internal pages and satellites.
Well you can't make too many per day if you do it manually. I'd go for high PR blog comments =) ******** if possible.
I agree, blog comments can't hurt especially if they are manual and sound like you actually read the content. I get frustrated seeing only spam comments on my blogs.