Which FCorrin to use

While sniping for Green and Blue today I got my final FCorrin to make her 4*+10. Now this last one happens to have some pretty decent Nature (+atk HP-). My old one is +Spd and Res-. Now I was wondering which of these I should use, since for 4' Corrin it is kind of an odd case
how her IVs play out. Normal 5* Corrin loses 4HP with a HP bane and gains 4Atk with a Atk Boon, but the 4* version already has these 4th points in her base stats, so to say, she only gains/loses 3 points but in exchange her base HP/Atk is one point higher/lower. Her speed is 3 points below the 5* version, regardless of boon.
I intended to mostly use her for her Breath weapon and try a surprise build using Lunge, Savage Blow and then going for the kill by the rest of the team jumping in with WoM to aid the damaged but hopefully alive FCorrin. Fury is supposed to help her get in WoM HP range.

These are her Stats when fully built with a +Spd Refinement:
Current version at +Spd -Res:
HP: 47
Atk: 47
Spd: 44
Def: 39
Res: 23
The other version would instead have
HP: 44
Atk: 50
Spd: 41
Def: 39
Res: 26
The lower HP and higher Res also kind of help getting her in the HP range of WoM I believe.

Also one thing to keep in mind, I ended up getting a Myrrh from this banner extremely early and I thought about using her alongside Corrin since shes the best Dragon I have that can make use of Hone Dragons a lot (Tiki dgaf about speed), so I think I should maybe rather get her to 56 Attack rather than 50 Speed when buffed. What do you think, which is better?