Preaching to the choir. Cadex not only has limited action support outside of Rem700 actions, they also are incredibly opaque in terms of getting drawings / technical data on any sort of chassis dimensions or top rail hole spacing here in the US. I'm on a first name basis with a few of the folks on the Cadex side as a result of this pursuit these past few months, along with some very helpful engineers at Zermatt and Defiance.You're going to be in for a rude awakening if you plan to use a Cadex chassis that has the monolithic top rails that run from the action to the hand guard...the scope rail holes on a Zermatt Origin are not the same as the Rem700. Not gonna happen.
You could make it work, but you're not going to like the cost. If you're going to use an Origin, you're going to have to have a gunsmith fill and drill new scope base holes....OR have a custom rail made. You're not going to like either one.
In case anyone else attempts this in the future and is looking for data from anyone else stubborn enough to attempt this, please find the following info below:
If you'd like to put a Zermatt Origin (SA) action in the Dual Strike, you want to select / purchase the version of the chassis they specifically design for the Defiance Rebel Medium. This is because both the Defiance Rebel and the Zermatt Origin are true round bridge actions, unlike the Rem700 action that has a flat rear bridge where the action rail sits. As @c_bass16 has pointed out however, the action hole spacing is not the same... The reason we want the Defiance Rebel version of the chassis versus any of the others is that the two front screw hole locations betwen the two actions are exactly the same - it's only the rear two holes that are different between the Origin and the Rebel.
I am electing to leave the holes on the Origin action exactly how they are, and am having a custom modified top picatinny rail made, using the Defiance Rebel rail as my starting piece. The two rear holes are getting plugged and then re-bored to be correct to the spacing of the Origin action. See attached for a drawing I made, taking prints from both Zermatt and Defiance so you can see the hole spacing comparison. I hope this helps anyone else looking to do any sort of custom work with top rails for either of these actions.
Total cost to modify the top Cadex action rail will be $250-$350. This includes plugging the two rear holes in the existing rail, boring them in correct position and cerakoting the rail black again. In the scope of my project ($900 action, $700 custom barrel, $1800 now-discontinued suppressor, $300 trigger, $2500 chassis, $3000 scope / rings, $800 bipod), the extra few hundred to make the whole thing work isn't exactly exciting to spend money on, but well worth it to solve the bottleneck.