I would be very cautious with this combo, personally. This is not the same as methylone + ketamine; methoxetamine is a DARI and a D2 partial agonist, among a slew of other things (it most likely has a broad binding profile: NMDA antagonist, (partial?) mu agonist, sigma agonist, K+ channel blocker, NACh antagonist, etc etc and who knows what, what I'm saying is that its not so easy to predict the safety of combinations with MXE).
My instinct seems to tell me that methoxetamine's dopaminergic pharmacology might be more similar to PCP than to ketamine. I obviously don't have any data to back that up, as MXE is unstudied, but its just a feeling I have. Anyways, given how cracked-out and dopamine fueled methylone can be-- especially after redosing-- I would honestly be pretty hesitant to combine it with MXE.
Fuck being a guinea pig, ya know?