Feedback on my Galeforce Eliwood build?

I really need to clean out my box and I have nine Eliwoods just sitting there, so I'm thinking 4* supermerge. I never pulled Brave Roy and I really want in on the Galeforce + Heavy Blade action. This site does have a Galeforce Eliwood build listed, but it gives him L&D, which I think just makes him into an inferior version of his son, so if I ever do pull B!Roy, Eliwood just winds up benched. But Eliwood does have one thing that Roy doesn't, and that's resistance, so with that in mind, this is the build I've come up with:

IVs: +spd -hp
Weapon: Blazing Durandal
Assist: Reposition
Special: Galeforce
A: Fury
B: Desperation
C: Speed Ploy (fantasy)/Ward Cavalry (reality)
Seal: Def Ploy

At 4*+10, this gives him an unbuffed stat spread of 37/54/38/28/37, which doesn't seem too bad to me. With horse buffs he'd be a god. I chose the Def Ploy seal to make extra sure he can kill things, and if they ever give us a Speed Ploy seal I'd be willing to sacrifice an Arvis so he could run both. Alternatively, I could go for the Atk Ploy seal if he's having trouble triggering Heavy Blade (especially if he's not on a horse team).

A concern I have is that if he's running a ploy for a seal he's not running QP, but with 37 res I could always have him tank a magic hit on his first turn to reduce cooldown and possibly trigger Desperation. (And if he's up against someone who can hit back and he's able to double, he'd trigger Galeforce anyway, right?)

Suggestions and feedback very much appreciated!