with people interesting in 1s 3" and also KababFPV working on it, i just want to try it too, for fun :)
rx3020 are very flimsy, so you might not want to try them. but they fly pretty good.
hq3020 are better.
i just used whatever i already have to build it. if you want a better setup, i think you should wait for what KababFPV come up with or follow someone with more experience with 1s setups.

it's more like for beginners or for some reason you have to have it.
it's extremely quiet. and you can't really hurt anything or anyone with it.
of course, it's a lot faster than those small whoops.

frame: 6g 3" , i'm using tweaky zappy 120 whoop frame and i can't find the link when i find it i'll post. but there are plenty different frames.
weight: 36g dry, i used nylon standoffs and screws to save weight.
not nylon screws by themselves alone that would be too weak. so use half nylon standoffs and half screws.

batteries: 15g 1s, mine are 600mah crazypony. but there are better batteries around that weight.
propellers: rx3020, they're good but too flimsy, HQ3020 are better than rx3020. i think gf3018 are great too. but i don't have any with 1.5mm holes.
motors: hyperlite 1103 ( with white wires ) KV is about 12000kv
FC/ESC: crazybee v2 5a with internal RX, which you can't go far but it keeps the weight down
cam/VTX: aio cam with vtx chopped off and tbs pro32 vtx

Betaflight 4.1.0
PID is more like for people who don't know how to tune at all or it's a starting point. ( in the picture )
it's cold here, so i can't tell if the motors get hot or not. so check motors for temperature.

11/12/19: i'm still trying to get used to the quad and the place. as you can see the place is small and i can't really fly anything but 1s