Hi
vol_trend and lt_trend are chart related and depend on the settings and timeframe of the chart and are lagging indicators. You are right on lt_trend but I'm not sure how vol_trend works. I think it relates to increase or decrease in a selection's volume percentage.
For your purpose I would suggest sorting your selections by volume, and then selecting the top volumes
for example:
...your conditions followed by
and selections sorting order is defined by volume
and selections trigger expression match_index is between matching_number -3 and matching_number
this will pick the top four volumes.
the variable volume is the sections volume percentage in the market
if you wanted to work with the actual matched volume on a selection, replace volume with:
market_volume*(volume/100)
again, you can do the same with voldif_ e.g.
...your conditions followed by
and selections sorting order is defined by voldif_5
and selections trigger expression match_index is between matching_number -3 and matching_number
this will pick the top four selections whose actual matched volume increase is the highest during the last 5 minutes