Hello.
There are several positive things that you did not mention ;-)
You dont have to true the stone, and you dont get the sludge that occurs from ordinary stones.
That it takes twice as long with DF relative to SB is normal, due to DF is 600 grit and SB is 220 grit.
As I mentioned earlier, SB is the Tormek stone that is the fastest for grinding.
What I've found is the fastest way to grind for me with tormek is:
Starts with CBN 80 grit, then goes to DC-250, then to DE-250, then honing (this gives me razor sharp edges in the 50-60 Bess range. (you could possibly go from CBN80 to DF-250 and honing, but I prefer the added fineness of DE-250).
This is a bit faster than just using the SB-250. Although I have to change wheels several times, I prefer it instead of grading the SB-250 to fine and rough.
Regarding the water spill you are experiencing, this is normal, especially when using ACC.
I've dropped the ACC and only run clean water, this spills less.
So after I finish the grinding for the day I run all the wheels with ACC while using a toothbrush to clean the stones. (tormek does not recommend this, but I have done it for 8 months without seeing any hint of rust).
Even