You don’t need to get everything 100%. Usually, you need to get 100% or almost 100% of the radicals you learn at the beginning of the lesson right. The kanji you learn at the beginning of the lesson don’t matter as much because you have the whole week to guru them. Then you need to get the second batch of kanji you learn midway through the week close to 100%. As long as you guru 90% of the kanji, you’ll level up.
What’s equally important to accuracy, though, is doing the reviews (and lessons) at the right times. I could get into more detail, but it’s been spelled out elsewhere, notably by @jpspereira in a well-known post:
But anyway, that’s pretty much the answer. Going at 7 days or less isn’t for everyone. Go at whatever pace you feel comfortable with. Personally, I like it because I can structure it into my week efficiently, and I basically want to get through WK as efficiently and quickly as possible preferably having everything burned within two years. But others have different priorities.