Just a newbie question here... I'm on my 3rd/4th week of playing so I'm still relatively new with these advent event mechanic, and there wasn't much posted in the wiki about this so please bear with me here...

I have enough materials to get a duplicate of either Yatagarasu or the SSR weapon. The noob question is, should I get the second copy of the Yatagarasu/SSR weapon and prioritise both of them to max limit break ASAP, or do I get the first copy of both SR assault weapons and/or the grimoires and get the dupe Yatagarasu/SSR weapon after the shop have refreshed?

Also when does the event shop refresh? Is it during the daily reset?