Some people don't like running Solidarities, or running 3 Cyber Dragon (a lot of people run 2) or running 2 Machina Force (most run 1, some run 2). Play test and find out what works best. Also, you would run 3 Pot of Duality, but they're going for about $90 apiece, and I assume your friend doesn't want to spend $270+ on 3 cards. On top of that, some people run 2-3x Book of Moon, but I don't think that's necessary with 3 Dimensional Prison and 3 Smashing Ground.
Some people don't like running Solidarities, or running 3 Cyber Dragon (a lot of people run 2) or running 2 Machina Force (most run 1, some run 2). Play test and find out what works best. Also, you would run 3 Pot of Duality, but they're going for about $90 apiece, and I assume your friend doesn't want to spend $270+ on 3 cards. On top of that, some people run 2-3x Book of Moon, but I don't think that's necessary with 3 Dimensional Prison and 3 Smashing Ground.