Amps, Speakers and Ohms.

I just bought a B52 4x12 cabt. for $120.. But there's only one mono jack wired to the cabt. . There's no stereo option. It was modified. The speakers are all 16ohms.
It's wired like this.
Positive on mono jack.
v
v
-v----v-----v-----v = + contacts
(+)_(+)__(+)_ (+)
(16 )(16 )(16 )(16 ) = Speakers
(-)__(-)__(-)___(-) = - contacts
^-----^----^-----^
^
^
Negative on mono jack.
I have a Mesa Dual Rectifier with output jacks for 4, 8, and 16 ohms. If the speakers are all 16 ohms, which output jack would I use?
As I understand it, it works like this:
(1/16 + 1/16 + 1/16 + 1/16) = 4/16 = 1/4 = 4ohms.
Is this right?
The second part of my question is this. If I wire a second input jack to it, to use it in stereo, the formula would look like this:
RIGHT SIDE
(1/16+1/16)= 2/16= 1/8 = 8ohms
LEFT SIDE
(1/16+1/16)= 2/16= 1/8 = 8ohms
My amplifier has 2-4ohm jacks, 1-8ohm, and 1-16ohm. Would it still be ok to use the 2-4ohm outputs of my amp if I wire it like this:
RIGHT SIDE
Positive on mono jack.
v
v
-v----v
(+)_(+)
(16 )(16 )
(-)__(-)
^-----^
^
^
Negative on mono jack.
LEFT SIDE
Positive on mono jack.
v
v
-v----v
(+)_(+)
(16 )(16 )
(-)__(-)
^-----^
^
^
Negative on mono jack.
Or would I need to have 2-8ohm outputs on the amp?
It's wired like this.
Positive on mono jack.

v
v
-v----v-----v-----v = + contacts
(+)_(+)__(+)_ (+)
(16 )(16 )(16 )(16 ) = Speakers
(-)__(-)__(-)___(-) = - contacts
^-----^----^-----^
^
^
Negative on mono jack.

I have a Mesa Dual Rectifier with output jacks for 4, 8, and 16 ohms. If the speakers are all 16 ohms, which output jack would I use?
As I understand it, it works like this:
(1/16 + 1/16 + 1/16 + 1/16) = 4/16 = 1/4 = 4ohms.
Is this right?
The second part of my question is this. If I wire a second input jack to it, to use it in stereo, the formula would look like this:
RIGHT SIDE
(1/16+1/16)= 2/16= 1/8 = 8ohms
LEFT SIDE
(1/16+1/16)= 2/16= 1/8 = 8ohms
My amplifier has 2-4ohm jacks, 1-8ohm, and 1-16ohm. Would it still be ok to use the 2-4ohm outputs of my amp if I wire it like this:
RIGHT SIDE
Positive on mono jack.

v
v
-v----v
(+)_(+)
(16 )(16 )
(-)__(-)
^-----^
^
^
Negative on mono jack.

LEFT SIDE
Positive on mono jack.

v
v
-v----v
(+)_(+)
(16 )(16 )
(-)__(-)
^-----^
^
^
Negative on mono jack.

Or would I need to have 2-8ohm outputs on the amp?