On v3, unfortunately many adc pins are unavailable with wifi 9n. Pin 33 works though.
Very recent Pixelblaze have a new revision that exposes more pins, a lot more analog. These just started shipping. If you need more than one input I can swap yours out for the new rev.
The voltage divider for the v2s esp8266 is a bit different as it can only go up to 1v. The v3s esp32 can do 3.3v, so no divider needed unless you have a 5v analog signal.
There’s no problem using the 3.3v, it has some headroom for light current loads.