Question about Divine Veil

[Zari]

I usually time it when healers are topping up prior to raidwide damage ( eg. Before seph ex p3 begins.

Can use clemency to activate it. Cross class cure cast is a but too long and not worth the slot imo but it costs less mp than clem i guess.

So it would be better to use clemency to activate it if necessary? Don't they have the same cast time? I just want to be sure which would be better so I know whether it is worth it or not