Near-native Chinese speaker here. (Started as a toddler and did it for 10-11 years in school depending on whether you count kindergarten, including rather formatted essays commenting on social issues and government policies, but lived in an English-speaking environment otherwise, TV dramas aside. Hence, I don’t dare to claim full ‘native speaker’ status. My Mandarin has currently fallen into disuse because I’m now studying in France, where Mandarin is nearly useless in daily life.)
Some people feel that writing kanji out is a waste of time because they could instead by learning new words or doing more reviews. This is true to an extent, especially if you only wish to understand Japanese, and not to use it actively in writing. However, my experience is that I’m able to tell similar kanji apart precisely because I know how to write them. An example that (perhaps thankfully) doesn’t apply to Japanese, but which appears in Traditional Chinese:
壹 (traditional complex form of 一, generally used to avoid fraud on documents like cheques)
臺 (traditional way of writing 台)
You might think they look way too similar to tell apart initially, but if you know the stroke order, you can find ways to remember which is which by targeting the things that make them look similar. For example, both of them contain a 口 and a 冖 somewhere in the middle. Knowing stroke order, however, you can say that in the first, 冖 comes before 口, whereas 冖 comes after 口 in the second.
Also, with all the practice I’ve had, I honestly remember words by seeing the kanji write themselves in my head, so… yeah, I’d say it’s very helpful.
I don’t use the WK SRS at all; I’m just here for the forums. However, from what I’ve seen in Level 60 posts, it seems that even for the fastest people, clearing levels requires 6 days per level. I understand how tedious it is to have to keep doing the same thing over and over while wondering whether you’ll ever be done, but I’m just not sure if what you’re considering is reasonable. (I’m not here to be a wet blanket: if you believe that you can do it, by all means, go ahead. I’m just saying that you might have to consider what you’ll do if you can’t finish all the levels in time.)
Ultimately though, it’s probably going to be real life exposure and usage that will help drill kanji into your head, so you might not need to worry so much about your reviews even if you start to get overloaded. I sincerely believe that flashcards can only do so much: I only remember one of my French flashcards right now: “s’effondrer” = ‘to collapse’. That hasn’t stopped me from becoming fluent in French, because everything else has melted away into the vocabulary I actually use on a regular basis.