Hi tubby,
You will find a lot of useful informations and operational procedures in the airport briefing charts, under the sections that deal with low visibility. Usually airlines develop their own procedures regarding low vis ops during taxi, such as specific briefings, anticipating/delaying the checklists to be both heads up when the airplane is moving, specific taxi speed etc..
Since you will undergo a recurrent training on that subject you should check with your operator if there is any company material available to apply your standard.
Concerning your last question, you need to check with specific airport restrictions and your company restrictions. For instance getting to the holding point and being stuck there because your minimums (for any reason) are higher that the runway required minimums doesn't make sense. Better wait for a stable RVR improvement that meets your criteria to avoid wasting lots of fuel and delaying other airplanes at the holding point.