You don’t make water soluble cannabinoids by adding distillate to “a powder”. You need to make an emulsion & then later you can (purhaps) convert that emulsion to a powder.
~80mg/ml THC “water soluble”. Can be made into a powder by desiccation (vac oven). 1/2 teaspoon (~200mg) into a commercial soda (plain soda in the middle).
Recipe is not mine to give away, but there is plenty of discussion here on how this is achieved.
Powdered THC isolate is NOT where you need to be looking.
Same trick, after desiccation. Although this one used CBD isolate rather than THC crude as the cannabinoid source, and I still need to powderize it and figure out the potency.
ThC potency was fine tuned based on bioassay. Which doesn’t work so well for CBD 
Edit: and then the CBD from above powderized, via oster blender tek
