Which configuration.. and how would I empty the water from either?

How would I empty the water from this configuration?

Hi guys. I have all my parts.... my case has an internal box with the pump and heatercore inside of it... Two hoses coming in and out of the internal box. I don't want to have to go into the internal box if I can get away without having to. But for either of these two setups... what do I need to do if I want to empty the water from the system (to remove a pc component or change all the fluid) ?

Please ignore the cutoff valves.. I have two and can place them anywhere.. The res at the top also normally has two plugs, but I can attach a barb and tube at the top if I want...

Thanks for all suggestions and explanations...


edit: Removed second configuration. I didn't like it.

What if I put a t-valve between the gpu and the northbridge, have the cutoff valve going to the res from the NB on, turn on the system and have the pump push the water out of the heatercore through the CPU block, the GPU block, down the t-valve into a bucket?

When I see the res empty out, I could then turn off the system, open the cutoff valve between the NB and the res by turning it off, and let the remaining water flow down throught the NB, down the t-valve into my exit tube. Would this work?