Depends on the steel really,I like the Congress Tools MoldMaster stones for doing fast work on normal kitchen knives,for harder to sharpen steels you can I like the Venev stones and I also like the Metallic bonded CBN or Diamonds.
I would glue the Chosera stones to blanks if I were you to give them more backing and make them stronger incase you push to hard when you sharpen,I do not soak the Chosera's for any longer then 15 minutes and with a guided system you still need to wet them often if you are having to use the stone for a while,also type on ebay rust eraser get a medium one I use them to de-glaze the stones I always had problems with my KME Chosera stones always glazing over after only 2 use's and it got to the point they just wouldn't remove any metal until they were de-glazed.
I also have the 3 set of Spyderco stones and really like them and do not seem to wear at all and depending on the edge you like they are great for maintaining your edge they do cut a bit slower then some other stones if you were to use them by hand but when I use them on my Tsprof they seem to not be to bad if you already have a good edge that's not been abused and just needs a touch up.
If you like really polished edge's I'd look at getting the Suehiro 10 and 20K the 10K is better then other 10K out there,the will also last you a very long time.
Also look up Michael Emler on youtube he is a really good freehand sharpener and use's a bunch of different stuff.