Six in back plus two up front is fine. With six HMMWVs, even with six additional drivers, there's still enough space for the entire platoon.

Add external stowage racks for rucks, spare tires and other gear.

BAE produced a field-installable armor kit for the M1152 that provides armor protection for troops in back as well as five weapon stations.

http://www.baesystems.com/ProductsSe...152_troop.html