The Spyderco UF ceramic depending on some variables is very close to a 8k Shapton Glass waterstone. The Shapton Glass are the closest you will find to a Spyderco ceramic, its similar in that they are both ceramic abrasive and while they cut steel they also have a burnishing effect that adds to the luster and polish of the bevel.
Beyond that, they become very different stones. The Shapton Glass are very hard and dense stones but still work like a waterstone in that they release used abrasive to expose fresh sharp abrasive allowing fast metal removal.
The Shapton DGLP is a very nice tool but at $400 its not for the non-professional. This is where the Atoma 140 comes in, the Atoma has an engineered surface that works exceptionally well at lapping the surface of waterstones and provides the surface texture needed when using a high density ceramic abrasive. Surface texture is important with these stones so using a quality diamond plate really can improve the stone performance and feel. When using the Atoma 140 plate to lap the Shapton stones you can use a bit of pressure when starting out but never lean into it. As you start to come to the end of the lapping process lighten up on your pressure and float the diamond plate on the stone. This will smooth out any deep grooves in the stone created by the diamond plate and allow for smoother sharpening feedback.
Will the SG500 take out the Atoma 140 scratches? Yes, but there will come a point where any one of the following will make it more difficult... increased bevel width, increased hardness, or increased wear resistance from super hard alloys (niobium, vanadium and tungsten to name a few). For most pocket knives and average kitchen knives the 500 will quickly wipe away the Atoma scratches... using light pressure with the Atoma will also make the transition much easier.
I recommend these three stones in combo because they can and will sharpen a wide range of cutting tools from damaged and dull to semi polished and very sharp in the least steps possible.
Do you need Shapton stones to do this? Not at all, I can accomplish similar with a hardware combo stone and a strop but that's because the skill will always trump the tool. So why do I recommend the Shaptons? I recommend the Shaptons because they take away the variables that cheap sharpening tools add into the mix. The closely graded ceramic abrasive, consistent feel, consistent sharpening action and finished sharpness all make for process that is faster, easier, and less stressful for the beginner. These stones simply produce results without fuss.