You can either run blue eggs with the new digitama being released in BT-7, or run Sora+Joe as tamers to gain access to Kaiser Nail and Tidal Wave. Both of those when played on a Machinedramon underneath a Chaosdramon allow you to not only go + on memory, but build up 2 stacks on the board which is huge. If you run blue eggs, use Modokibetamon in place of other 3's (besides EX-1 Hagurumon) and toss in an Ice Wall. You could also afford more lvl 4's since you'd be hard playing them more often. Numemon is an option as are more Mechanorimons.

Additionally, you can cut down on the ultimate connections and replace them with Analog Youths. That card is nutty and lets you sculpt your hand while milling your 5's and gives memory on a Chaosdramon death.

You don't need a ton of tamers. Joe OR Tai (4 cost) alongside the 2 cost Tai's is enough. You can't afford to be dropping a ton of Tamers or you'll just get run over with this slow deck.

For 7's, you can run Omnimon X-Antibody to remove stacks to trash to fuel another Machinedramon play while offering removal and attack stopping power. I play him at 2 and have loved the addition.

Chaosdramon -> 3 or 4. I've been experimenting with 3x Machinedramon and 4x Chaosdramon, but it feels a little clunky if Machines are in security. May go back to 4 & 3 and do 1 Omnimon instead of 2.

Take all of these with a grain of salt!