Beginner Electric Ranger question

Hi,

I have some question about Electric ranger:

1- Should I put Electric Damage Rune on my bow or rather put Physical Damage to boost shock, electrocute and skills damage ?

2- I used passives to raise my Electrocute Built Up by 50%. Will this be enough to procs electrocute or did I have to put a specific skill or add a support gem ?

3- I dropped my Widowhail (164%) in favor of a crafted bow with +2 level to arrow skill. Having a Quiver with +# level to arrow skill will be enough of an incentive to switch back or should I concentrate on Rare bow ? What should I look for on the Quiver ?

Many regards and thanks for your comments.