Ultimately I am trying to "pre assemble" my next scene (multiple clips and changing settings for multiple clips). You may be onto something with the cross fader and I will definitely have a look at that.
So far when setting up my decks, I have given great consideration to how I would trigger multiple clips at the same time, while also deselecting previous clips to achieve my next "scene" and only using a mouse. Sometimes the next scene (group of clips) involves playing with parameters. So I have these groups of clips in vertical columns, and column trigger is almost perfect. Except for that I have to trigger the column, which is now live for the crowd. Then I have to mess with parameters of a couple clips, while the audience watches?
I get that settings can be done individually, but that kind of defeats the purpose of a preview. If a preview only works for 1 clip, it just feels like preview could have more potential. If I could preview my column, tweak that full scene (clips in the triggered column) to get the look I am after and fade that in to show it to the crowd. That could be a really great way for VJs with *only a mouse* (which is key here, I already have DJ gear in front of me) to achieve the desired look (in preview) as everything takes longer with a mouse. I prefer to not do all that work while the audience watches or individually on each clip 1 at a time.
As far as your description, I did not fully follow it. But I am a newbie here, so I will fire up the software later and see if I can walk through it. I do like the crossfader idea though and I had not considered that. Ultimately as a DJ I am familiar with that concept. I will just have to try it to see if I can preview my "scene" (triggered column) that way. Which I assume must be possible or it would not exist.
I will say that the "clip specific blend mode" request may be the solution. In cases like the "mask technique" (3 clips, one is B&W, and 2 layer routers). I also had a 1 button Bump flash on the deck too (where the layer router needs "Multiply" blend mode). Then (being new) I can forget to change that back when triggering a Mask column. Now I am fixing a broken scene live. If I could preview... Or if I could set blend modes per clip... Same goal, but blend modes per clip fixes the source and is a better route over all. I would rather not have to troubleshoot as I am already doing 2 jobs, DJ and VJ.
So you see, I would not know that something is wrong with a full scene, as it can only be seen with all layers fully assembled. Previewing that is a baby step, but per clips blend modes. That is the fix.