I think that would do it. It's hard to get them lapped so everything is coplanar. If they have any saw marks in them or anything, it takes forever to get them out. I usually get most of them out and then just use them after that, with a focus on flushing the surface of the stone often to make sure any lapped particles don't remain on the surface.

The plainer the stone, the better. It might be my imagination, but I think the green part is a bit more dense and I like it a little better, but both the greenish and tannish parts work well.

I didn't think my jaspers absorbed water at all, but one of the prior posters was right. Mine will absorb water ever so slowly. Not like a synthetic hone, but just a tiny hair faster than the stone would dry off if it didnt' absorb anything.

I kind of like to break my stones in with razors if possible (not so much with an arkansas stone, but you can do it with the jasper) so that I don't get heavy handed with a tool and make a very very slight dip in the middle. That's more a concern on wide stones like the jasper pieces, but once they settle in, I wouldn't want anything smaller. If you have a spyderco fine or UF, that might also make a nice thing to burnish the surface with.

I think you'll be pleased. There isn't anything to lose except time, the stones are almost free. Even if you get some that are a bit too porous for razors, they make great edge aligners and polishers for knives, etc.