This workflow uses tiled sampling to sample large images in hirez fixes. The Tiled KSampler is similar to the Advanced KSampler node, so there's a couple imporant differences from the "standard" KSampler.
* denoise is handled through start and stop steps compared to total steps.
* using 30 steps, start at step 15 and end at step 30 (15 steps) is equivalent to 0.500 denoise.
* Tile Width and Height should be the maximum size the GPU can reasonably handle.