stacking

Just watched a You Tube video where the 1.4 & 2x teleconverters were stacked on a wildlife shoot. But did not see any images.

Does stacking these two work?

Yes it works; good on some top of the line lenses, and not so good on cheap lenses.
Remember, you're losing 3 stops of light, seriously degrading IQ and losing AF on all but a rare few lenses. I do it for moon shots on my EF300 F4/L IS and on tripod(a well as my EF70-200 f/4L IS), and also tried the stack on my 150-500 OS... for the short, short time i owned it.

Both these with 1.4 and 2X stacked on a Sigma 150-500, apologies for the cobwebs in the garage

Thanks for posting the images. How offen do you find yourself stacking?

Not very often