I only use and sharpen traditional knives. Carbon and low alloyed tool steels.
I've no experience with guided systems. I don't think it's practical or even possible to sharpen the narrow blades of traditional knives at the angle i like, between 10 and 12.5 degrees with such systems.
Whatever your choice, guided or freehand, you need:
A low grit (up to 1000) to set the bevels, restore a very dulled edge or repair major damages.
A finer grit (from 2000 to 5000) to remove the burrs you will get with the coarse stone, to refine the edge and maintain it.
For some tasks, like whittling wood, a keen edge is a pleasure to use. For that you have to use very fine grits (8000 and upon). Stones this grits can also be used to maintain edges without excessive wear when a strop isn't enough for that task.
I sharpen freehand since fifty years, straight razors, knives, axes. I'm not an expert, just a good average or an average good sharpener in my good days, but there's one thing i'm sure of. Never use strength when sharpening, no excessive pressure on the blade. If you use the right grit the stone will do the job. This way it will be easier to keep a constant sharpening angle. Enjoy.
Dan.