Pro Mini + Nrf24L01+ PA LNA Node power options

Hi, I'm a noob at Arduino programming, and currently making my way to make single lipo powered nodes to measure soil moisture sensor and relay values back using nrf24L01+ PA LNA. I'm using a pro mini. I want to summarize all the doubts I have, and if possible get insights on them

  1. I've read that powering the pro mini directly via the Vcc and not RAW will save precious battery as the ams1117 wont take consume battery (better than physically removing it?). My only concern is that while the lipo is at full charge it rests at 4.2V, will giving the Vcc 4.2V be alright?

  2. There are a lot of threads mentioning using a voltage divider and analog A0 to measure the battery voltage, but I couldn't find a tutorial for noobs like me to understand how to make a voltage divider, could somebody pls help me with the resistor values? My max battery voltage is going to be 4.V

  3. I tried the lm1117v on a breadboard first to experiment powering the nrf at MAX output, while using 10uF capacitors each at input and output, I was getting voltage drops to 2.8v (from 3.3V) at every transmit event of nrf, however switching to 100uF capacitors made it quite stable, are 100uF capacitors excessive? if yes what values should i use?

Thanks in advance