I'll try to get a pic of my platin mod tomorrow, basically it has a 1/4" x 1" piece of metal machined and polished added to the platin to extend it up a little and gives you a higher and narrower platin for the 1" belts so you can "V" grind the edge if you want too. There's plenty of room above it to do a convex edge also. I'm currently doing both, it just depends on the knife and use. A member of another forum did the mod for me.
As for belts, I really like the 3M Imperial Micron Poly Belts. You apply very little pressure (basically just barely touching) to the belt. I have them from 100 down to a 9. They do a very quick job and when done right the knife is scary sharp. I do finish with a leather belt.
I also use 3M Trizact belts. I have a A100, A80, A65, A45, A30, A16 & A9. Again depending on the knife and the use will determine the belts I use. I also finish with a leather belt and compound.
I also have a few AO belts just in case I need to do some heavy repair/grinding.
So far Super Grit seems to be the best place to purchase them. I have not found them any cheaper, they ship very fast and are very reasonable.