There is two schools of thought with flushing.
Flush for 3 days in coco or 7-10 days in soil to use up all the nutrients. It shocks the plant and supposedly makes the smoke cleaner. Flushing will bring the ppm down. If you use light nutrients in the flush it will do a better job.
The other school of thought is no flushing. Just bring the ppm down slowly near the end. These folks are very meticulous about drying and curing. They definitely soak in a solution either lemon and baking soda or peroxide and water, fan dry then line dry. A long cure will breakdown and remove nutrients too.
I've done it both ways and prefer the slowly reduce the nutrients route and a good cure. No one I know can tell the difference anyway.
Always options when growing. Since your plant is very amber, I'd go for the good cure. Maybe next try a few different methods and see what you like best. Everyone develops their own style or signature method. There is no right and wrong, only what suits you.
Congrats on getting it across the finish line! ES