Need help with configuration settings

I'm currently running the TPC-H benchmark with 25GB of data on a
Linux/PostgreSQL system with the following spec:

2 x Opteron 1.8GHz
16GB RAM
2 x 3ware 8506-8 controllers
12 WD Raptor 74GB drives in two RAID 0 arrays

Can you make any recommendations for system settings?
Should we recompile to change the default page size?
If so, what do you recommend?
Do you have any thoughts on optimum RAID stripe size?

Thanks in advance.

Barry Geipel
barry@GeipelNet.com