If you want it more durable for Arena, you can easily focus on Seraph and use Light mark + Rays.
Either way, for this deck I would use 3 Seraphs. You'll draw them often enough that you'll be able to use 1-2 of their abilities and play them earlier thanks to towers/pends, whereas you'll have the Rubies for those draws where you get more quanta.
Also, SoF > Explosion thanks to Cremation.