I purchased a GEPRC Li-ion VTC6 4S 3000mAh Battery Pack.  This is my first and only Li-ion battery.  I wanted it for long range gentle flying.

Unfortunately I know nothing about Li-ion batteries and can’t find much online that helps.

Here is what I have figured out.  For charging this battery and to extend its life, I will be using the Li-ion setting on my charger, maxing out at 4.1V and using a rate of 1.5A.  I was told that the battery will get warm. Is this all correct?

When flying I found that it would be a good idea to land when the battery reaches 3V. Is this correct?

I found nothing on storing this battery type. I don’t plan on flying once it gets cold here is Canada and through the winter months. What is the storage voltage.  What the self discharge rate per month?  Are there any other parameters that I should know about?

Never used iion for FPV but the bare 18650s I have that get charged off a simple charger at .5 amps does slightly warm the batteries so I'd expect a little warmer at 1.5 amps.

Everything you mentioned is correct. Storage voltage should be around 3.8V. The discharge in storage will likely vary depending on the quality of the cells. I find that most li-ion have very minimal discharge in storage.