I was playing a couple of days ago and I was running a Vic 2 with warlord and overload pulse. The question that came up was when do the crit effects or in this case spending the crits take place? I was thinking that i could spend the crit after rolling to use overload pulse to exhaust their defense tokens. If thats not the case then that would kind of eliminate my strategy to a certain extent. And also, if you activate a crit effect then you can not use it for damage correct?

Yeah, bad news, but the crit goes off after the target has gotten the chance to spend tokens against that attack. The first time every person who has ever used OP triggers it and finds this out, you can see their world come crashing down around them. :/

Page 2 of the RRG details the steps of an attack. You can see there that the Spend Defense Tokens step comes right before the Resolve Damage step, during which "The attacker can resolve one of its critical effects."

The way OP works, you have to use it to tee up a shot for a second ship (or a second shot from the same ship) to take advantage of.

OP works as intended - either the opponent uses his def tokens against the attack or they get exhausted anyway. This creates a tactical advantage, preventing your opponent from saving his green icons until he needs them. Plus a ship can't use more than one of each type of token per attack, so ships with doubles are in trouble.

The critical icon is still added to the damage total! It just doesn't trigger any more critical effects (like the default 'first card dealt faceup').

Now with wave 2 you can use Scree and a RAIDER to trigger the OP, rather than wasting a front arc shot from a Vic. Makes it more palatable, no? 8 pts for the upgrade is still quite expensive though.

Good news is, if they spend their defense tokens on their own because they think you'll exhaust them anyway, you can still do the standard crit. If they decide not to use any defense tokens, then your attack goes through unmolested AND you can exhaust their tokens.

I'm still trying to get the 1-2 punch using some other ship with OP and the Avenger title on an ISD, but so far I can't seem to pull it off (probably because I don't own a raider yet).

Could go gunnery team on 2 ISD set up. 1st one fires on two ships exhausting the tokens. Avenger comes in with gunnery team and fires away. Couple with screed to make sure you get the crit.