Guidelines for Striping?

I searched the usual places and could not find a definitive "best practices" type guide on creating striped metas. I have read here and there that multiples of 8 meta members is a good rule of thumb, whenever possible, but I have yet to find any EMC documentation that states that explicitly (could be me, I dunno?).

Additionally, if the "8 meta members" for a striped meta recommendation is followed, I would like to know why 8 is the magic number. Is this generally for best performance, regardless of host I/O? Additional questions...

How about, for example, if you prefer to use 50gb meta members, but only need 250gb meta. Would 5 meta members not provide as good performance as 8? Or 11, or 13..you get the picture.

Also, are there any recommendatons for replication of striped metas via SRDF?

Would appreciate some good documenation on this topic, and of course, feedback. Thanks