Render Region on 2.79

Currently the render region is a 4 step key combination which totally takes the attention from the screen to the keyboard.
First step: CTRL+B
Second Step: Drag and release a box for region draw area
Third step: SHIFT+Z
4th step: Render representation on Cycles (which I don´t know why calculates and says: “Packing VBH”)
5th step: SHIFT+Z
6th step: CTRL+ALT+B

Too many steps for a render region.

Given we have a render region, how possible could it be to add STORED views on it? We can´t compare any changes on the current render with another change from before.
Render region should be a 1 key combination on-off for every user. This is also standard on the industry as we don´t need to check the entire scene rendered, but only a part of it from time to time.
The abiity to check and match previous settings (view/shading/) could be added on top of any render region view. Just like modo, cinema or Softimage.
Thanks.

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