Any tips for flushing the engine coolant system as well as the heat exchanger?

[weider1717]

First inner cooled car I am familiar with flushing coolant and burping but what is the best way and place to drain the heat exchanger.

 

Also my car is an 07 so I will be using the ford GOLD coolant do you guys recommend the premixed 50/50 they offer or the concentrate and add distilled water myself and make it maybe like 70% water and 30% coolant.

 

Thanks