This app was mentioned in 6 comments, with an average of 6.00 upvotes
I prefer this one, because it has all the Unearthed Arcana and SCAG spells. More importantly to me you can edit the custom spells you add (which as far as I know you can't do with that app) and you can import them if you have the premium version.
The OP's cards do look a lot nicer though, so if it's released I will certainly take a look.
Maybe a spare character, just in case? If your character is a spellcaster, maybe check out this app. Also snacks to share are always nice :)
My spellbook app of choice is Spell Book Burned on Android. It's updated with all the spells, even UA (not sure if it included the new batch of cantrips and 1st level spells from a couple weeks ago yet), makes it very easy to manage spell lists for multiple characters, lets you take notes (though, unfortunately, the notes are on a spell, not a single instance of the spell: as far as the app is concerned, it's not just my Tiefling that can only cast Hellish Rebuke once per day as a 2nd level spell). I guess you can have it track spell slots, but I do that on my paper character sheet because that makes the most sense to me.
Right now I use this, I used to use this, but it doesn't work on my phone now.
I would get a dry erase board to write down the initiative order and put one of your players in charge of letting players know who's on deck. To make spell casting quicker I recommend using an app to quickly look up spells and track spell slots. I use this one. If you still have issues with long turns I would give each player 2 minutes then anyone on the table can start a 1 minute timer. I would only do this as a last resort.
It's awesome.