Since the ATK of Twin-Barrel Dragon is 1700 and same to that of Axe Raider, the highest ATK level 4 monster you can get, you need to use equips spells or other ATK boost cards to get your monsters to defeat the dragon.
Use Spell/Trap removals
Destroying Keith's Machine Conversion Factory, Second Coin Toss, and Rare Metalmorph is important to help your monsters to beat Keith's Machine monsters.
this would be a consistant solution to counter his removals but only for targeted monsters, the problem is that he still can target ritual cage and destroy it which breaks all the effort onto setting this up. I havent grinded as much yet to aquire 3 copies of Devine Grace - Northwemko yet so I cant tell if there is some play around it.