dawn is fairly harmless to plants, it only takes a small bit, 10-20ml per liter. I wouldn't spray it at all this late in flower though unless I was very careful(or the buds are still fairly small, if they're chunky at all I would be careful). You could make a solution of dawn/water and go through just wiping the tops and bottoms of each leaf with a rag or something. Bugs like to live/lay eggs on the leaves not the sticky buds anways. I've never personally sprayed dawn soap in flowering, but I imagine it would leave a residue on the buds.
If you have a hydroponics store nearby you should go buy a little bottle of Azamax or whatever similar product they have. Its like 20$ or something outrageous for the tiny bottle, but you only need like 10ml per liter. Its ingredient is organic and won't leave a residue all over the buds, so you can spray it even like a week before flower. Spray your plants every week or two with it and you shouldn't have any pest problems. Stop spraying a few weeks before harvest. You can also water them with it, idk how much of a difference this makes though.
Make sure you don't soak the leaves while the light is directly on them, the water will heat up and burn the leaves. I spray my plants right as the light is turning off, and keep a fan blowing gently on them all night so theyre pretty dry by morning.
