Chain Lightning

[arrunique]

I have a softcore lightning sorc at about level 94 or 95. She was actually my first char to beat 1.10 baal so I leveled her starting with almost no gear.

how many points are required in synergy skills and mastery to make lightning, chain lightning and charged bolt usefull in hell?

All of them. Every skill point other than a couple of utility points should go into the synergies for chain and lbolt. If you only play solo you might get away with dropping some points into orb but if you want to be able to function in party play you need to specialize.

or even thunder storm.

Thunderstorm is a waste of skills in pvm. It is both too weak and too unpredictable to be of any use.

Can firewall hold its own without maxed mastery?

Firewall has sexy damage numbers but in practice you can't use it solo, monsters simply move too fast.

Unfortunately you can't practicly hybrid with the lightning tree. An orb/charged boltress might be possible but you really need damage reduction gear because charged bolt is pretty much a melee skill.

On the bright side lightning immune monsters (except for the trees) are the wimpiest so a buff merc can take them down. The downside of the lightning tree as opposed to the other two trees is you can't assist your merc with static.

Lightning builds are particularly dependent on fast cast gear. They are also really mana intensive.

If you happen to be on US EAST ladder hardcore I have a +3 lightning amulet with damage reduced by 20 I'm willing to part with.

Good Luck