This is why I shoot with a 600mmm

[Lez325]

The bokeh from my 600mm prime (a Rikonon 600mm f/8 mirror lens) would be far more distracting - it's one of the reasons I don't use it much.
At least it's considerable more affordable than yours & a lot less effort to lug around.

In the right situation I think my 300/4 & 400/5.6 options might be able to approach the smooth bokeh you've got, but they certainly would need a lot more help from background distance.

Even my dreams don't stretch to the Sony 600/4, it's way to far out of my class.

Yes f8 doesn't really do BG and a 600mm is a beast to be sure a 300mm f4 will give the same Bokeh as a 600mm f4 to be sure - but not the range- something we wildlife photographer 's all suffer with is lack of range - not much we can do really- if you add a TC you loose the bokeh& image quality no win situation all round

Les