RSU sale and w-4 adjustment?

Hi there. 
Two questions at once please:

 

as part of my comp package at my job I have RSUs…the grant date was 12.22.22, the first (of a few, sequentially) vesting date is October 15th, 2023. I’m trying to make a good decision insofar as selling to lighten the tax liability…

my understanding is that the LTCG tax is 15%, the STCG is 22% based on my income level (about $84k).  
ao it appears I have enough time in calendar year 23 to sell them (on/after 12.23.23) in order to realize the better tax rate, right?

And, would adjusting my w-4 (currently filing  single, claiming 1) have any impact?

 

thank you!!