I have used all sorts of plates and stones for flattening, currently I use an 8" diameter 180 mesh diamond disk from Kingsley North. It flattens everything. I agree the Norton 220 is not a very good example of the coarse waterstone, the King 240 is better. Though most coarse waterstones are not fun to use anyway. This is the stone I use currently for setting bevels and bridging to the 1k, work great with a long soak in water:
http://www.nordicskaters.com/produc...ds/1605/zandstra-foss-elite-sharpening-stone/
The Norton are a real nice stone for most steels. Are a bit expensive for what you get, but do a good job - an excellent job on carbon and low carbide stainless, and hang in there even on HSS but really at their upper limit. They work best in a straight progression to the 8k, or at least to an 8k microbevel. Can make a good edge at 1k and 4k but because they're a softer stone they need a light touch and some finesse to get the best from them. Once learned they are a quick, reliable stone.
I can't not recommend them, but there are a lot of options out there. The set I picked up from Suzuki Ya have a similar feel to the Nortons but are far harder, dish less, and cost about the same. If you get a good deal on the Nortons they're a great set, otherwise I'd think about shopping around more.
And if you get into waterstones you will want a good lapping plate, and to move all around on the stone to minimize dishing and any ill effect from sharpening on a not 100% flat stone.
