Hmmm...Yeah, for action duels, maybe just use it for deck shuffling (unless we're heart of the cards-ing those since they're PVE) and use it for the usual kind of duels otherwise? I don't remember Duelingbook having a time limit, and while there is a chat system I don't know if it lets viewers talk in it. (The reason I'm pointing to Duelingbook instead of other programs is that it's all manual, and you can make custom cards on it because of this, so it seems to fit well.) The big issue would be having to RP it out as the duel goes on so we could copy-paste it all into a collab, then do any edits necessary as a duo before one of the two duelists posts it.

[@Double]
Well, Darkness Metal Dragon is a fantastic card so obvious it would be really good in any dragon deck, but maybe add it back in and then he builds a red-eyes deck as the RP goes on? Alternatively, there are less situational ways to handle a Horus Synchro if you decide you want that concept. I just thought that since it'd be really strong it would make sense to have it be a "Majestic Dragon" Synchro.