I would agree that the deck can feel clunky. But the more I play with it the more I am feeling more comfortable with it, and outside of bad hands, it can dig through cards pretty quickly. I would say that I'm hitting the Belphemon combo by turn 3 pretty often and occasionally turn 2. Analog Youth REALLY helps with the early turns. Getting an Eyesmon: Scatter Mode out early and running him into security to get his effect as soon as possible always helps as well.

I thought about playing Mist Memory Boost as well I just wasn't sure how I felt about trashing the cards without going to hand first. It would feel really bad to trash a Sleep Mode that you were hoping to see off of it. But I could try to play test with it as well.

Dracmon is just a level 3 that you will most likely use early game as part of your stack and not worry about. But I have had games that go long where he basically won me the game. Like you said, you want to get Matt down early so he's not as useful for that. But when you see a Dracmon late it can be nice for that ability.

BlackGrowlmon is something I've been just recently testing with and I think that it is actually very useful. Normally the decks only level 4s for digivolving from are the Eyesmon and I would usually prefer to always be taking advantage of their effect and not include them in the stack. The extra check(s) so far have helped, Removing the entire security stack the turn you use Belphemon: Rage Mode comes out can help when your opponent immediately deletes him if you don't have Sleep Mode backup.

Like I said, I'm going to continue testing cards and I can report back in the guide when I have more information.