Unfortunately I’m not really an expert in the physics of nonclassical fluids. I personally put a giant dot in the middle and squeeze down to minimize the chance of forming air pockets, and based on experiments applying it between two transparent acrylic sheets, this method seems to work well.
You might be interested in a more scientific test, which suggests that as long as you don’t leave a thick layer of paste under the MCPCB, the way of application doesn’t really matter.
From this, it is reasonable to also infer that the quality of the paste doesn’t really matter either. Even the cheapest, crappiest thermal paste would do if you apply it well. This should not be surprising, as LEDs are much simpler and more robust devices than CPUs.