With Subterfuge Mask, would you use an int helm or a dex-int helm?

"Subterfuge Mask: +2 to Evasion Rating per 1 Max Energy Shield on equipped helmet."

Int helm, only shield, max it, bonus evasion from passive.
Dex/Int helm, shield and evasion, access to % evasion increase, and still some bonus evasion from passive.

I took a quick glance at the trade site without getting too strict about the search, and it looked like I could get roughly the same evasion for a given price either way. At least at the moment I checked.

Assuming that your question was "I am looking for the best mix of evasion and energy shield while evasion is prior stats for passive defense and energy shield is for effective HP"

In current version, pure ES helm (around 450ES/0EVA -> 450/900, absolute max may be 550/1100) seems to be reasonable choice. It cannot be too hard to find one with 450 ES helm in any situation.

INT/DEX helm would reasonably be like 200ES/500EVA -> 200/900 with the key passive.
200~250 ES difference is not small while top end INT/DEX chest can be 450ES/1200EVA -> 550/1200 with key passive (Spectral Ward), and top end DEX chest can be 0ES/2200EVA -> 180/2200 with key passive.