I did some tests yesterdy (pics to follow). A Tripod is something really great!
The 190 is large enough when extended and feels sturdy. I am happy I choose a tripod with only 3 segments per leg! The 484 ballhead looks smaller than expected, but it does the job.
Concerning the load capacity: My heaviest lens is the 28-135, adding two TC brings me to a bit over 1KG. Absolutely no problem. I am confident that adding another 500g (for a 1.5Kg lens like 70-280 or 70-400) will be a non issue.
It's not too big and the height is enough for me. If I extend the mid section to it's max, I can't see through the vw anymore. However then sometimes I noticed a slight shake when pressing the shutter and I could see the difference between using the remote, 2s MLU or pressing the shutter. Anyway, I extend the midsection to about 40% for my size and things are fine.