The
GW version Apocalypse book is actually awesome. Use those missions and rules for scoring. It came out just before 7th and maelstrom but it's a good middle compromise.
Everything scores, and you score by closest model regardless of distance (3" or 10" whatever), also you score at the scheduled breaks, which might seem like a funky mechanic bit it's absolutely necessary. Plan out your day and your meals/breaks (have food ready) and have an idea how long you want each turn to go.
The new Warp Storm cards, I forgot the name, would be pretty fun to add, however they do seem like they'd be 'more' fun if both sides had psykers.
The
Apoc book also has some nasty and devastating rules like "unnatural disasters" that we generally save for later rounds if we need to speed things up and kill off more models.
Apoc is great fun, take pictures! ...here is the final leg (part 3) of our last mega Apocalypse:
http://atticwars40k.blogspot.com/2014/11/apocalypse-on-ordel-v-final-assault_19.html