Neither, go with con.
On a more serious note (and take note I’m only lvl 158 so most of the things I know is second hand information) INT and SPR benefit different skills.
INT:
Better Cure damage.
Better healing and damage on Heal
Better aspersion, and by extension apergellium damage (because of the 10% class rank bonus to INT and STR, 70% higher INt from sta allocation at job 7).
If your last two class picks have good magic damage (like druid or plague doctor) it will add to that.
SPR:
Stronger stone skin.
Better deprotect zone.
More mana (should be a fairly minor benefit if you’ve reached 7:th job advancement).
Magic resist.
Note that aspersion and mass healing scales with SPR, so while inferior to INT you can still do some damage
That said, the overall consensus seem to be that Chaplain is a crappy pvp class, since the class requires you to run up to enemies and smack them, and most opponents are never going to allow you to do that.