grinding standings to get the lowest tax rate

I already maxed out my skills and did the epic ark missions. I only have need to get my standings up to get the lowest taxes rates.

I have 2 questions

1- if you took the time to do this how long did it take you?

2- i notice my corp standings is going up slowly with every mission, and assumed my faction standing would also be going up but at a much slower rate. but its not. Do i have to do a certain number of missions before i get a boost to my faction standings or something?