Hi, I'm pretty new to this myself too - but, I have the experience of trying to cycle a tank with food and shrimp and failing myself. (The readings never went over 0.5ppm). I think you'll have a better time with the pure ammonia, which is what I'm using now.
My understanding is, yes you can ignore the instructions on the bottle and just add the ammonia until you get a 4ppm reading with the API kit. I got lucky, added a 1ml pipet of the ammonia solution I bought, and got a 1ppm reading. So then I added 3 more pipets and hey-presto 4ppm green
My understanding is also that you need to keep it topped up to 4ppm by testing the water and adding more ammonia as required until the nitrites start to show up.
I was wondering if you have plants in the new setup? Because I am under the impression that having plants in my tank when I tried the shrimp-method was the reason my ammonia reading never went above 0.5ppm. Plants can directly use the ammonia as fertiliser, so my cycle never started. Plants is not a problem, I am in the process of trying to cycle a new planted tank with pure ammonia solution, and this time it is working! It's just worth knowing plants act as a buffer for ammonia.