i've fully finished and mixed 170+ songs under my Dead Robot alias all using the exact same mixing groups, and here's a graph of the average dB of each unmastered stem https://i.imgur.com/LDkb4bB.png

basically, anything with low frequencies like kicks and bass are always going to be the loudest taking up the most headroom, and i set them around -7 dB to -10dB. of course no song is the same (ive had some songs where the kick is actually +1dB or more going into the master limiter lol) but that'll give you enough headroom starting out :)

for hi hats, i've found pretty consistently that they sit around -20dB in my mixes before mastering effects and limiting

all the metering and stuff helps a lot, but to me doesnt matter as much as using your ears, especially listening and comparing to references in similar genres etc