Quickly tested this
This lens should also handle teleconverters well, even the TC20, but I didn't test those. Weighting almost three kilos, lens can be still used some times even handheld but monopod/tripod is recommended.
This is intimidating looking big piece of glass if used by portrait photographers (unless you are paparazzi and need the distance).
Best thing to test heavy telezooms like this. Once you switch back to your normal zoom/prime lens, camera feels lightweight :)
Padded case (CL-L1) comes with the lens. 300mm/f2.8 is quite compact when lens hood is attached to it reversed way. 24-70 next to case for size comparison. Sure, the case is still bigger than smallest DSRL camera bags.
As there wasn't any live wild animals available, stuffed weasel worked as test subject for testing 300mm/F2.8 VRII. VRII works great, this was taken handheld at 1/50 shutter speed.