Best raid option

[GTK-ZNZ]

My company has just purchased an HP Integrity rx2800 server which has (among other things) an HP Smart Array P410i controller with 8 300GB (HP 300GB 10K SAS SFF 6GB DP). The server will run OpenVMS and a somewhat light commercial application

Two of the disks have already been factory configured as RAID 1+0 with OpenVMS factory installed

I want to configure the remaining 6 disks.

The original thought was to create one raid array of 5 disks leaving 1 as spare.

Now considering a raid 5+0 using all 6 disks under 2 parity groups (in fact when I get into the configure menu, this is the default option it presents).

What is the most recommended option?

Neither performance nor available space is a big consideration as the application is light weight and does run adequately on a much smaller server

What I am trying get here is other users' confidence levels on the two options above and also factors like how crucial is to keep a spare disk, how easily can one be sourced if no spare disk etc.

Thank you !

[GTK-ZNZ]

(I meant RAID 5 as the first option)