Follow earlier entry in thread for table sizing, but i would prefer have the extent size constant and equal to extent size set for tablespace.Only reqt of doing of sizing of table is to decide on which tablespace to put this table on.I suppose you have different tablespaces for small tables,medium and large.


For LOBS, it deoends whether you want to store in row data or out of row that is you want to define seperate storage space for lobsegment or you want to store in the table storage area.

IF out of row (which should be the case if high update and query and size is more than 4K) follow tamils response.To add to that chunk size should be equal or multiple of oracle_block_size and depends on the type and amount of IO.
And set PCTversion also depending upon whether and how many users would simultaneously read the LOB, if high concurrency and high number of transactons , keep PCTVERSION high.
Logging , if u have a standby database or want recoverable option for LOB then use LOGGING , also depends on whether u want to use cache or not.
Cache takes lot of db_block_buffers and causes lot of misses for other objects.Use only if the transaction size and chunk size is small.
READ/Write is done in chunk size.

thanks
GP