Ethereal Knive Totem Support Gems?

Playing as a Marauder for this Build... What would the Support Gems be for a Crit EK Totem Build?

With the Minimum 3-Link Setup the outcome would be Ethereal Knives - Spell Totem - Faster Casting

My current planned options...

Faster Projectiles - 10% Cast Speed
Slower Projectiles - 10% Projectile Damage
Iron Will - With Marauder you can easily have 300+ STR so that'll be a high bonus to the Spell Damage
Added Fire Damage - Extra Fire Damage and alot more than the one granted by Herald of Ash.
Added Chaos Damage - There's still this little rare drop-only Gem that's definitely an ideal choice as well.
Increased Critical Strike Chance - Going EK along with some Spell Crit Nodes from Witch & Templar that would make the Totems have higher Crit Chance as well.

disclaimer: i'm not a totem guy or even a spell guy

what about spell echo? with a crit based build, you may want more casts/second if your crit chance isn't really high.

iron will and added fire are good.

crit gems you will have to decide on the fly based on your base crit chance/multi

wouldn't do slower projectiles...that would be more useful for something that can hit multiple times and/or curse or some crap

wouldn't do added chaos if you are not scaling with other chaos damage or poison mechanics

Spell Echo doesn't Work on Totems though so that's one Gem you'd worry less about it.

Currently my Setup now is Spell Totem - Ethereal Knives - Faster Casting - Iron Will

When I get a 5th and or 6th Link it'll be Added Fire & Faster Projectiles.

So I guess i'm sticking to my current setup then.