Despite it saying this on the FAQ’s of the MRP web site:
What kind of cranks is the 2x compatible with?
The 2x is compatible with a wide variety of cranks from several different brands. It was originally conceived to work with the new variety of double cranks on market, but it can also be used with traditional triple cranks. To use with triple cranks, you must remove the outer ring (generally a 44t) and swap some washers in the guide’s pulley assembly as outlined in the instructions. You should not change the position of any of the other rings. You will need either short chairing bolts or chainring bolt spacers if converting a triple crank to a double configuration.
This is the official line:
The chainline wont be correct for your chainset.
The lower guide has restricted movement, and it won’t get close enough to your 33T middle ring. It will compromise your chain retention and security.
So to chanage a tripple ring XO set up so it is compatiable with the new MRP 2x chain device you need to change both the remaining chain rings and the spider 😡 !