I think the bester 1200 is a fine choice. I use it frequently and it's a good and consistant cutter. Our number 3 selling stone on the site.http://www.chefknivestogo.com/bester1200.html
For low grit stones there some good choices. The Chosera 400 is one of my favorites. It's fast and consistant. The Shapton pro 320 is another good stone. It's splash and go and cuts well. Yes you can flatten all your stones with sandpaper, usually 120 wet dry is good for this. If you flatten a lot you may want a diamond stone down the road like the DMT but it's not necessary.
The Beston 500 is another stone you might want to try. It's our #2 selling stone. It's a good cutter, drinks water and dishes kind of fast but is easily flattened and works well.