SRT these days is best done with either one of the friction sharing devices (Hitch Hiker or Rope Wrench) which combines a closed friction hitch with a mechanical device, or one of the new all mechanical devices (Rope Runner or Bulldog Bone).
A closed friction hitch is one that has both sides terminating in a knot or a spliced eye attached to your karabiner (VT, Distel and many others), an open hitch has one end attached to your 'biner, the other end free (Blakes, tautline).
A Blakes hitch is not recommended alone for SRT, it WILL bind with all your weight on it ion the one leg of your climb line...remember when climbing DdRT your weight is shared between the two sides of your climb line.
As always, if I'm off base on any of this, someone else more experienced will chime in to make sure you are not directed too far off track!