@shookieTea Welcome to WaniKani and the forums! I really hope your journey is a nice one.
On reading Genki
Just to be clear, I didn’t get the majority of my grammar knowledge from Genki (I’m not even hating on Genki, it’s a well written textbook and if I didn’t have other options I would have been grateful for it).
Instead what I did was once I had some grammar knowledge from elsewhere, including being able to read simple texts, I went and read through Genki. Like, just read it line by line. I read all the English, I read all the Japanese in the order it was written in, chapter by chapter. I looked at what the exercises were asking me to do and didn’t do any of them, I just kept reading. This will not teach you grammar in a comprehensive way, it’s not a new way to learn things from a beginner level. But it is useful enough to solidify concepts that you sort of know from other sources, and a nice complement to other ways of learning if you know for whatever reason that you’re not going to stick with Genki in the way it’s intended to be used.
The workload on WaniKani builds up dramatically over time, and you have to be careful not to bite off more than you can chew by doing lessons faster than you can keep up with the reviews for.
Maintaining a 7 day leveling pace is very ambitious and not for everyone and carries a real risk of burning out, there are horror stories all over the forums about this. The best pace to go at is a sustainable pace for you, please don’t pressure yourself into doing anything unsustainable for the sake of going faster, it’s not a race.
A general rule of thumb to test whether a workload is sustainable is to look at the number of ‘apprentice’ level items you have. Many people find about 100 is a good number to aim for. I rarely went above 150, others like to do fewer. The higher the number, the more reviews you’ll need to do in a day. You’ll need to find a number and workload that works for you as you get to higher levels.
The specific answer to your question depends on your accuracy, because the more you get items incorrect the more reviews you will have. And be prepared - accuracy falls as you get to higher levels, since the differences in the kanji get more subtle and it’s easier to get confused with things that you’ve learned already, unlike at the early levels where everything is new.
I started with an accuracy rate of 98%+ and it fell to about 80% by the end. With this accuracy, I was able to do seven day levels doing no more than 250 reviews every day.
To achieve a 7 day level time, or close to it, you’ll also need to be careful about the timing of lessons and reviews, and do them more than once per day, at least 3 times per day in fact. For literally every question you might have about pace and reviews and timing, please see this post which answers it better than I could, and with cute gifs. It’s essential reading and has helped me and others out no end, no matter what pace is right for you My Journey of 368 days (+ The Ultimate Guide for WK 
) - WaniKani / Level 60 Celebration - WaniKani Community
Most of all, good luck and enjoy the learning!
@kuchikopi I love how encouraging you consistently are to others in this forum. I have also definitely noted your insistent demands for 
on others’ level 60 posts 
Look forward to reading your level 60 post real soon and seeing your cake! 頑張って!