Anyone have formula or advice on what to set the size of this parameter? Can't find anything on Metalink that gives some good advice.

Here's my situation..
I want to implement db_32k_cache_size for a tablespace that I want to use a 32k block size for. However, I don't have any references or ideas as to how big I should set this buffer size to. 10meg 100meg ??
The tablespace is going to be holding nothing but LOBS of 200 meg and above.