boot - How to hide grub unless key is pressed?

I have 2 OSs Windows 8 and Kubuntu 16.04. Kubuntu is my primary OS.
I would like my laptop to boot directly into Kubuntu, unless I press SHIFT key during boot to make Grub menu visible.
Again. I want grub menu with OSs list visible, only when I press SHIFT or any other key during boot.

I followed instructions in Hide GRUB2 menu UNLESS you hold down Shift key: how to make this happen? and it didn't work as I wanted.

I don't even want to feel that the grub is there, so the following values are required.

GRUB_HIDDEN_TIMEOUT=0.0
GRUB_TIMEOUT=0.0

Apparently linux doesn't give you the freedom it tells you it does. Because if it did /etc/grub.d/30_os-prober wouldn't change the timeout on its own.

if [ "\${timeout}" = 0 ]; then    

set timeout=10

Is there any easy way to achieve what I want? Thanks in advance.

EDIT:

It does not work.
Additionaly according to
info -f grub -n 'Simple configuration'

'GRUB_HIDDEN_TIMEOUT'
     Wait this many seconds before displaying the menu.  If  is
     pressed during that time, display the menu and wait for input
     according to 'GRUB_TIMEOUT'.  If a hotkey associated with a menu
     entry is pressed, boot the associated menu entry immediately.  If
     the timeout expires before either of these happens, display the
     menu for the number of seconds specified in 'GRUB_TIMEOUT'             before
     booting the default entry.


     If you set 'GRUB_HIDDEN_TIMEOUT', you should also set
     'GRUB_TIMEOUT=0' so that the menu is not displayed at all unless
      is pressed.

     This option is unset by default, and is deprecated in favour of the
     less confusing 'GRUB_TIMEOUT_STYLE=countdown' or
     'GRUB_TIMEOUT_STYLE=hidden'.

I set GRUB_TIMEOUT=5 and GRUB_HIDDEN_TIMEOUT=3 and grub menu is shown for... 3 seconds!?

Clearly people behind grub, screwed it up.