I know how you feel with the fear of forgetting. When I first started WK, I was so terrified of forgetting things that I took every word from WK and put them into an anki deck, set the intervals as low as possible, and ended up reviewing everything every few days. Eventually it became too much and I stopped studying WK words outside of WK. Now I review WK vocab at WK’s intervals, and that’s it. I noticed that my retention has hardly dropped at all. So I was doing 500+ additional reviews daily when I absolutely didn’t have to. I wasted so much time trying to be a perfectionist that I could’ve spent on other things. And sometimes I do forget things, but either the SRS takes care of it, or I see it in reading material.
You won’t really have to worry about forgetting things until you burn them, when they won’t show up in the SRS anymore. Unless you decide to go quite slowly, you won’t likely be burning things until you are passed level 11 and reading will help solidify those kanji after that point. You can also always add burned words or leeches to an anki deck (that’s what I do, still a bit afraid of forgetting, I suppose) and review them indefinitely.
I went on a bit of a tangent, but basically, it’s okay to forget things, and the extra work you put into doing everything perfectly is probably unnecessary. SRS works great when you let it, you don’t have to worry. I wouldn’t bother getting vocab to guru before progressing, you don’t have to do that, and it will probably slow you down considerably.
As far as leveling speed, the first two levels can be done in about 4 days, and every level after that can be done in about 7 days at max speed. Average leveling speed seems to be around 10 days.
For reading, I don’t think you need to wait until level 11 or any specific level. Grammar will hold you back far more than kanji, since kanji are easy to search, especially if you’re reading stuff online. You should start out with easy material like Tadoku Graded Readers or NHK Easier. With NHK Easier (a version of NHK Easy with extensions, basically), you can hover over words and see the the definition and pronunciation of any kanji or word. Even if you were at level 11+, I still recommend practicing reading from these or similar resources before diving into books. Reading definitely takes some getting used to, and I think it’s good to work your way up in difficulty, even if just to give you the confidence boost of “hey, I can read something!”