Interesting questions.
There has been significant research done to analyze vortices. Due to the number of factors involed, there is still little understanding of the vortices themselves or the mechanism(s) which create them.
There for a while, winglets were touted as reducing vortices, but that had no scientific foundation, and is generally discounted these days.
Releasing an agent from the aircraft will not show the size or strength of the vortex. We have seen many videos of water and smoke in NASA and other agencies trials, but these have failed to illustrate the size of the vortex influence.
There is nothing that can illustrate the velocity of the core of boundary elements of the vortices. There are currently attempts to use SODAR and LIDAR systems to measure size and location of the vortices.
There are many videos online which show the condensation trails, these may be a closer illustration of the vortex boundaries. Attempts to create that on final approach would require immense amounts of water and the right conditions.
ATC does take into account aircraft size in the wake separation tables. Winds are not taken into account in the wake sep tables.
There are some trials which attempt to take crosswinds into account for closley spaced parallel runways, but these are very preliminary.