[TEC] ParticleGenerator/FastParticleGenerator

[gap]

a bunch of questions, sorry:

1) What's the difference between these two render controllers?

2) Is there any difference between SHIII and SH5 FastParticleGenerators Removing SHIII ones and adding them back in Goblin Editor don't seem to make any difference in game, if the same settings are applied...

3) Is it possible to preview FastParticleGenerators settings without having to run the game, as done with the "normal" ParticleGenerator? Merging baza_FX.dat and particles.dat in Gobli Editor, allows me to know wich material is selected, but then particles are not generated along the 3d model preview

4) What the controlllers WaterInteraction and WaterSurfaceTransition do exactly?

5) Is there a way to trigger a generator within a given depth range (as done with GenHeightControl/FastGenHeightControl), but only when object's depth is decreasing (or increasing), so to generate different particles depending on the direction of vertical movement?

All of the above questions apply to the whale unit that I am currently converting