Dont't concentrate on number of hyperlinks, concentrate on top quality on back-links. It is ok to get few hyperlinks from public information but of you want to make improvement then consider to do visitor publishing.
I think there's no magic formula of how many backlinks you need to post everyday. It depends on the quality of your website, your keywords, your competitors, your contents,...and many other onpage factors. However you should try to focus on quality instead of quantity, I think so.
There is no specific number of backlinks for per day. It is up to you how good quality and relevant links you are generating. For blog posting and article submission you must consider 1-2 post in a day are genuine post
On an average getting 4 back links one day, 8 on next day, 5 on third day, 3 on fourth day... there is no limit how many posts you do. Answer the posts where you know its answer well.
How many backlinks per day are safe depends on the backlinks. Backlinks from blogs i would say 1 toi 2 a day is safe.
Backlinks from directories i would do 3 to 5 a day for a few days then submit a few more every few days or week are safe. Social media 1 or 2 per site per day.
Do not try to get alot of backlinks everyday google looks at that and knows that it is not natural to have so many links show up in a few days or week.
Try to get a few good backlinks everyday from different sites like blogs and social media and directories. Make sure the backlinks are from similar topic site and use seo for any backlinks.
You need to concentrate on the quality of backlinks rather than quantity because quality backlinks will help to get higher rankings and generate more traffic to your website.
I think in 2017 no of backlinks does not matter but the quality of links. it does not matter how many per day but it should be less than 5 and only from high quality sites
First look at your competition.
Second, there is no "best practice" for "daily backlinks". Link profile should look natural. That means that you should build your links consistently.
Don't focus on a number of links, focus on quality on backlinks. It is ok to get few links from social profiles but of you want to make progress then consider to do guest posting