nps
1
yes blending modes are a bit sucky and is a bit of a hackaround, varying degrees of transparency depending on look your going for is about the best we can do
best bet instead of white is 128,128,128 layer then add your coloured filter layers on top
saturation could be done with a pattern, for example checkout the very last pattern style for body which by default is a dark brown color dodge layer, if you combine that with the warmer colours esp red, purple for example then it really has a nice rich saturation
2
you can create javascript scripts to run within ps, checkout the bitmap font script i did a while back on the sc forum in byteworks i think for an example or even quicker is to create an action as its fairly basic to clone the layer and change the hue
3
heh y almost
well i would like rgb layers implemented personally seeing as there is no coding behind the XUIs' in Xion
therefore we could plant on top r,g,b layers with an already set transparent look(variable depending on the saturation needed) which would then have 3 sliders in the main xion interface for the skin options, all r layers would then be set according to slider value, same for g, b layers, that would be ace!!
depending on how you setup your rgb layers would also mean that on specific sections you could also create the colour relationship of items for say a triadic color scheme (3 fixed colours round the spectrum wheel)
and the sliders would keep the relationship as the layers would already be preset
so that leaves a lot of potential color changes
for a basic skin then at least the spectrum and whites/blacks/silvers/golds etc...