Pros / Cons of Equal Length Control arms for IFS

What are the pros and cons of an IFS that has equal length Upper and Lower control arms ???

I remember reading about suspensions awhile ago and I remember there was a reason why IFS systems have shorter top A-arms ??? DOes anybody know why ???

I am planning on making a completely new front suspension....that has equal length upper and lower control arms....they will give more lift with suspension I have designed... And do I need to tilt the spindle 3 degrees back form horizontal, for antidive ??

Thanks for any help

Pete / Mayday