The 400 Latte is a great starting point for you on your dull Henkels... and on hard steel, as well. Just be sure to work methodically & monitor your progress regularly. A 400 stone can take off a lot of steel fast, and if you're not experienced, you can end up reprofiling a knife quickly. This can be daunting to correct at that skill level, but it is great experience.
There is a STONE SET <--link
that holds the aforementioned stone, as well as a reliably performing 1k... the Ume 1k. The Ume will give you a functional edge on your soft steel although I would strop them on the 5k Rika, to finish. Your soft steels will not benefit from the full monty on the 5k, but polishing off the 1k teeth, a bit
, will help refine your edge past that 1k bite.
On hard steel that can support the edge, that 5k Rika is an amazingly effective, as well as, pleasurable stone to work with, and the set I link to above is a very versatile bang for your buck.