Mesa 400+

I just bought a used mesa boogie 400+ Amp. I also bought 2 mesa boogie cabs. One is 15" for 8ohms 400 watts and the other one is 2x 10" for 8ohms 600 watts. (both are powerhouse Cabs). I am not sure how to connect my 400+ amp with this speaker cabs.

Can I use both cabs for my 400+ amp or oly One?
If I need to use both cabs, Do I need to plug in the 8ohms out put or 4ohms out put?

What type of connection that I need to use (I mean parallel or series)

Another question: Please help me to chose the appropriate case for my 400+ Amp. Which case is fit the best and works well for amp 400+. I heard people talk about 4 rack mount or 8 rack mount...or Not enough air flow.........etc.

Please help me out, I am a new bassist.....I did not know much about these stuff.

I'm new here, but if I'm not mistaken, you could hook those up one of two ways...

A) Use two cables running out of the two 4 ohm jacks on the back of the 400+... one cable to each cab.

OR...

B) Use one cable out of one of the 400+'s 4 ohm jacks into one of the 2x10's speaker input jacks... then use the 2x10's other speaker jack as a "piggyback output" to the 1x15 cab.

You can connect the cabs up just like the last reply said.Either way should work fine.As far as what rack mount to use Im not sure you could call Mesa 1 707 778 6565 and ask them.Take care of that amp it should last you a long time.And remember nothing else sounds like an all TUBE amp. Bruce