Help With Disk Layout

This is my first install on a RAIDed array and I could use some recommendations. I am planning on
just mirroring my transaction logs (no RAID) but I've been told to make sure everything else is RAID
5. I don't like it but we've got huge amounts of mirrored write behind cache so that makes up for
some of it. I know these questions are subjective but even general answers will be helpful to me. Anyway here are my questions...

1. Is there a problem with putting my System and Temp tablespaces on the same RAID 5 set along with one copy of my Control file?
2. If I'm using RAID 5 then is there really any reason to keep multiple members of my Redo Log Groups?
3. I will have the Oracle app itself ($ORACLE_HOME) installed on it's own RAID 5 set. Is there any problem putting one of my control files on this drive set? How heavily are the $ORACLE_HOME subdirectories really used?
4. Any further advice you may have on this subject is appreciated.

Thanks in advance,
Roger Westbrook
Dollar General Corp
rwestbrook_at_dollargeneral.com
(615)855-4378 Received on Wed May 31 2000 - 00:00:00 CDT