I actually started off using a flying morning star deck for my arena trials, but it didnt seem to be fast enough against gold or platinum, but that was probably my bad luck, as it took me almost a gain of 5k score to beat platinum with the deck i ended up going with, which stomped bronze and silver btw (gold was a pain, 3/4 rings too often, so i did plat)
I really recommend only using an upped version, although the animate weapons can stay unupped and be flying weapons, but that means changing from a light mark to an air mark, which does slow you down a bit.
This is the version I really like using.
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I like the excessive miracles just because morning glorys alone can be slow if you dont draw that animate. The sanctuaries help for early stalling while you wait for that needed miracle. Once you get that first miracle played, you usually have a terrific chance of winning, unless you come up against phase shields or even bone walls.
If you come up against a firestall, dont worry too much if your sanctuaries are destroyed. Also if a fire shield is played early, holding back your morning glorys while stalling until you can play at least 3 at a time is key to winning. Just hope they dont use too many sogs, any more than 2 out, you better hope for the best draws you can. 3 MGs still deal 14 dmg a turn against 2 sogs, which is plenty providing you can draw at least one more.