I just received my first Vision Grande a little while ago. While the concept is novel, I am not a fan of the whistle tip. There's massive amounts of vapor but it seems very airy and cool. I ran into this exact problem with the ego-T (which now sits in the pile of "Waste of Money" on my desk).
Since I normally vape 2.4-2.6 Fluxos on a standard Riva, these cartos shouldn't be much different. I've raised and lowered the plug and the only difference I encountered was leakage. I think the problem lies in the huge amount of space the vapor plays around in and cools before it comes out the tip. I stuffed the space in the cart with a paper towel which helped out a little and plugged one of the tip holes. There's just the gaping maw left in the tip itself.
Since I normally vape 2.4-2.6 Fluxos on a standard Riva, these cartos shouldn't be much different. I've raised and lowered the plug and the only difference I encountered was leakage. I think the problem lies in the huge amount of space the vapor plays around in and cools before it comes out the tip. I stuffed the space in the cart with a paper towel which helped out a little and plugged one of the tip holes. There's just the gaping maw left in the tip itself.