Efficient Boolean Storage

Hello,

I need to store many (e.g. 30) booleans and am wondering what is the most efficient way to store them.  I can think of four options.

Option 1...Use ‘bool’ data type

No good since each value will require 1 byte rather than 1 bit.

Option 2...Use ‘bit string’ data type

Good since bit status is visible e.g. 0001000110

Questionable...How much storage used?  Storage = 1 byte per bit?  Or Storage = # of bits rounded to nearest byte?

Option 3...Use sets of ‘char’

Good since compact.  Storage is known...8 booleans = 8 bits = 1 byte

Bad since less obvious to casual database viewer.

Option 4...Use individual ‘bit’ data types for each Boolean

Good since obvious to casual database viewer.

Questionable...Probably uses 1 byte per bit.

Thanks in advance for your help.  I’m new to PostgreSQL.  Yet, I’m architecting a database where storage space is at a premium.

- Chris