Considering a fluid head - A7Riv and Tamron 28-200

Craig, there are some complexities built into this and decent quality of a video head does not come cheap.  But, it's not about the head, but rather *about the results*.  As to the DPR video, Chris nailed it on one hand, but there are work arounds that were not explored fully.

Not having the 502 does not give me the right to badmouth Manfrotto, tho I hear echos from folks that the head still is jerky & saw a video to that effect.  When one slaps on 800mm or 200-600 lens things amplify tremendously and even playing back on a conventional screen (27") will show the problems....also, it depends to what degree one is a perfectionist and what stuff is allowed to slide.  In this context, Manfrotto is a relative "newcomer" to the video heads.  Maybe I'm old school, but I mostly respect the stuff that has been proven over and over under *variety* of conditions....and there are less than a dozen great fluid video heads.  Indeed, they are expensive, but you can count on these products.  The fluid heads can be heavier and lighter.  Sachtler, Miller, Cartoni make both.  I recall when Sachtler originated their line back in 1981 under the Arriflex umbrella here in US....and we (film workshop participants) thought it was the best since sliced bread.

As I indicated earlier, one can get a "light" carbon fiber tripod with a 75mm bowl and easily install good quality fluid head.  Whether it's RRS, ProMedia or Gitzo and perhaps couple of other makes that accommodate this.  The reason I bring this up, it's because this set up may be seen as "hefty", but is way lighter than the conventional video legs ....and without compromising quality.

Much depends how serious one is about the quality of results.  Maybe it's me, but shopping for decent fluid head is v. similar to buying quality sticks.