I personally have it set to 6 a day, though it's not everyday that I end up learning new kanji as I typically focus more on vocab. My advice would be to start small and see how high you can reach per day. I think a lot of people do pretty high numbers, but I feel that's too fast-paced for me even though I've been learning for years.
I don't know but you will burn out, or they will all blur together, if you try and do too much. Take it slowly. Also in between sessions of learning new kanji, finding reading material with the kanji you already recognise will be helpful.
First, just try a small number to see if you can keep up not with the kanji but also with words, grammar, etc. Because if it's too much somewhere, your daily routine will slowly crumble anyway. I often looked at what my schedule will be in few days before learning new kanji/words/etc (you can see the number of review you will have for the next few days, very useful).
And later, you will always be able adjust that number or to go for more once you get used to kanji. Or less if you feel overwhelm. But it's better to start with "too easy". Because SRS system can pill up the review very quickly after a few week (and that's often why beginner get overwhelm). Once you know your limit, weakness or preferences, it's far easier to adjust those kind of number.
