sorry to get involved but I wanted to understand things a bit better.
For how I know guiding, backlash in RA is meaningless as you never reverse. Or you shouldn't. RA is always moving, so the motor is always working against a weigh. Now, the guiding pulses should always be accelerating or slowing the motor, but never running in the opposite direction, as is the case with DEC. So that's why you shouldn't bother with backlash in RA.
Now, even in DEC, you shouldn't either. DEC errors account for polar alignment inaccuracies. In a perfect world, a perfectly aligned mount would leave the DEC motor off for the entire session. Of course this being impossible to achieve, the next best thing should be figure out where the DEC drift is heading (N or S) and correct only in the opposite direction, disabling the unwanted direction. The DEC should only have a drift, hence why you need to correct in one direction only.
Please verify what I'm saying is right, I always like to learn
Also, question to Alfred: are you positive the same amount of pulse moves your mount differently in RA+ and RA-? If so, please check that your mount have maybe a different guiding speed per direction? It sounds strange but you never know.