Ugh, been down this exact road. Honestly, your grinder matters way more than a 15 degree water swing. If your grind is uneven, super hot water will just over-extract the fines and make it taste bitter. I'd start at 200F with a solid medium-fine grind and only change the water temp if you still taste grass or sourness after that.

That part about the "visual anchor" making all the difference, I see it the total opposite way. For me, throwing a sketch at the AI just gives it more wrong stuff to copy. It locks you into your own bad drawing. Starting with just words lets the machine do its own thing from scratch, which is the whole point. My best results come from writing a tight text prompt and then letting it run wild for a while. Feeding it a sketch feels like trying to teach a dog to paint by holding its paw. You just get a messy picture.