How do you handle double deep turtle

Hmm, I've never actually beaten that list. I've come close by playing the scenario...

I hate to say it, but it's actually a decent match up for Karchev. They usually have a bunch of stuff to easily trigger Road to War off which really helps when the turtles keep repositioning out of threat. Also Jump Start covers the issue of your stuff getting knocked down all the time. Battle Charged not so useful since they will be knocking down your stuff, so you can't counter charge when they repo away.

I wouldn't have thought LoS would go that well into it. Usually they have plenty of Jam to get through and the turtles can kill a lot of infantry...

I think what you really want into it is no knockdown + counter charge on jacks

Rashet in winds of death is currently kind of a silver bullet for khador, most hard gunlines, such as nemo3, are. We have good raw stats but very few way to actually help us close the gap when overwhelming shooting is on the other side of the board.
What's your usual OW2 list?
I have yet to test it but I've talked about it a lot with one of our local player who just made it to the WTC Canada team, so a good player, and he said the best option is OW2 with rocketspam and it's still an uphill battle, but it's the best option we have at the moment.

I think once the armored corps stuff gets released we will have options to play against that. Strike tankers can do a lot of damage to a derp turtle, if you have a way to help protect them such as clouds, windstorm or a good armor buff (Strakhov2's feat comes to mind) They might be able to survive long enough to do some damage and possibly swing the attrition to your side. If you bring ayana & holt and ragman you can probably get a fairly big damage swing that allows you to kill the turtle without taking too much damage in return.
The first list I had in mind was something along these lines:
conflictchamber.com/#c3201b_-107b7p7pl5l4l4l3l39ul28M8I7Qgd7Qgd

Khador Army - 73 / 75 points
[Theme] Armored Corps (CID)

!!! Your army contains CID entries.
!!! You are using a pre-release theme.

(Zerkova 1) Koldun Kommander Aleksandra Zerkova [+28]
- Destroyer [14]
- Destroyer [14]
Man-O-War Kovnik [4]
Man-O-War Strike Tanker [5]
Man-O-War Strike Tanker [5]
Man-O-War Suppression Tanker [0(6)]
Man-O-War Suppression Tanker [0(6)]
Ragman [4]
Kommandant Atanas Arconovich & Standard [7]
Lady Aiyana & Master Holt [8]
- Koldun Kapitan Valachev [0(4)]
Man-O-War Shocktroopers (max) [16]
- Man-O-War Shocktrooper Officer [4]
Man-O-War Shocktroopers (max) [16]
- Man-O-War Shocktrooper Officer [4]

I'm still not sure about Atanas and having only one Kovnik, so the list is clearly still subject to change but the basic core of double shocktroopers all the tankers and the merc stuff should do a good job at making the derp turtle more manageable. The turtle are usually the models holding the zones, if you can tag them with kiss and a shocktrooper in ragman's death field the shield canon and the guns on the tanker can do a fair amount of damage to the turtles. Zerkova's feat and cloud are also very good tools to get a good board presence against a typical Winds of death list.
That's the theory anyway, I still need to actually try the list once the MoW stuff is official. That list should also be able to deal relatively well with Nemo3, I think. Not exactly sure about Haley3, it would be a grindfest for sure with a cloudwall on both sides... Ayana & holt do allow to maybe take care of the echos, not sure if it has a big enough volume of attack to actually deal with def 15 trenchers...

Blind from Gorman and OW2 have been pretty helpful for me.

How does V1 rocketspam play into it?

Yup I talked to McWatters, he has more experience against these match ups than I do.

At the moment the options are clearly limited against Rashet.

I don't think clouds are totally useless against rashet though, well not when playing Zerkova, yes the turtles will ignore it, but rashet's arc node and venator won't be able to ignore them. Being able to deny blood mark by blocking LOS is good in that match up. Zerkova's feat is also pretty good to protect the tankers and allow more turn of shooting. It would probably not be an easy game, but I'm clearly curious to see it on the table to see if the theory actually works.

I imagine Irusk2 Armoured Corps would work; I run double Strike and double Damage Buff, and my whole army is no-KD tough, which should help against the turtles. I've got enough blasts to deal with hordes of Venators. I just don't know how they'd fare into his feat and laser guided Blood Marks.