(Quick Question) in regard to merging my Cecelias

I am currently sitting on about 60,000 feathers, awhile back I wanted to unlock potential of all of my Cecelia's and eventually create a +10 5*. Should I try to do that or should I just make a +10 4*? The only other characters on my unlock potential list are sharena and my life and my life and death fodder when I need it...