Which Ephraim to focus on +10ing?

So, I've long decided that I'd mainly focus on Sacred Stones units. (this goes for collecting them too, and I know we have CYL Ephraim coming up but this isn't including him) Both Ephraim and Legendary Ephraim are pretty strong units, but I feel it'd be redundant to heavily invest in both. Both of them, though, have a bunch of investment as far as skills, though my regular Ephraim has no merges while my Legendary Ephraim is at +3. Also the latter grants a blessing, so there's also that.

Of course, we're getting another Ephraim focus tomorrow, so I wanted this advice in case I should actually go in for him.

Side note: while I do wanna buff him up lots, I'm afraid of the inevitable Legendary Eirika whenever she comes around.