Flame Sentinel Spectre Help

Hello everyone ,

I'm currently using 6L Shavronne with this gem setup ;
Raise spectre, spell echo, minion damage, LmP, fire pen and Faster projectiles.

I'm using EE with arc to get -fire/-cold resistance on monsters.

So the thing is there is no tooltip damage for flame sentinels.I got some problems...

1. I want to change my Faster projectile to something else , my options are (Increased aoe, Chain, Conc. effect, Ele. Focus, Controlled Dest., Pierce).

2.Which gem setup gives best clearing speed?

3.Which gem setup gives normal clearing speed but good dps on bosses?

4.Which gems are useless?

I know some people might say why don't you go to a map and try yourself etc.
But it's really diffucult to tell the difference some cases.

Thank you for reading. :)