2 tsp per quart. Should be tested on a small part before using on entire plant. It can cause leaf damage if too strong. Kills bugs dead on contact. Not to be applied under lights.
BTI stands for Bacillus Thuringiensis Israelensis and is a bacteria that infects the guts of larvae like mosquitos to kill. It's used for mosquito control around cities using airplanes to spray it or added to the soil in your pots to kill fungus gnat larvae. If sprayed alone with just water on flowering plants it might be OK. Harmless to humans if eaten or inhaled but not sure about if smoked.
I wouldn't spray canola oil on flowering plants. You'd be smoking it later and it would taste crappy if not be dangerous.
I've never used citric acid but it's not sprayed alone I don't think.
Almost anything sprayed on buds will be there in the final product. I once sprayed insecticidal soap on part of a plant 3 weeks from flipping to 12/12 and the finished buds from the sprayed area tasted horrible after cropping and curing.
Like the old adage, An ounce of prevention is worth a pound of cure. Update: 28.35g of prevention s worth 454g of cure.