RAID setup
 

I had a browse around some of the forums and how to's and didnt find anything along these lines, so here i go...

Im trying to install Red Hat 6.2 onto 3 400mb hdd's in a raid, using redhats software raid setup. I have clicked 'add new partition' and chosen 'raid' for each drive. on the first drive i have a 50mb /boot partition not under raid. I am wondering now which partitions must i create (/, /var, /usr....), what would a reasonable partition size be, and which RAID to set them under (RAID0, RAID1...). Obviously im trying to install onto an older system, of which the monitor only supports 640x480 @ 50hz, so once everything is installed if the resolution is to high for the monitor is there a bash command i can use to lower it?

Any ideas/suggestions would be a great help
nic