Experienced artists please....using a fixative?

I'm pretty much done with a painting I've been working on and want to use a fixative. Don't know if this is important, but i used oil pastel in some parts, acrylic in others, and oil paint as well. Last night I finished off a corner of gr with water soluble oil paint, and it seems to be drying faster than regular oil paint, but my question is can I spray it this early or does it have to be completely dry? Also how much will my colors change? Is there a difference of what gloss, semi gloss, and matte do to it (of course besides the shine, ie do they change colors differently)? If anyone can answer those three questions I'd appreciate it, thank you!!