Ball Mount Question

You can back up with the wdh installed, not a problem. They take slightly longer to hitch up because you need to tension the spring bars that are pushing the  front of the tow vehicle down but once you have it adjusted the first time its easy, and you can raise the jack to take the tension off the bars while hitching and unhitching. You will be attaching some hitch parts to the tongue for the spring bars to connect to and will need to allow some time with the rig on a flat surface to get everything set up right to begin with, but the improvement in ride, handling, and control is well worth it when you're towing with a (relatively) light tow vehicle like your Taco or my Highlander.  

You should also think about sway control as part of your wdh selection process. If you do a search on this forum you will find lots of discussion on wdh and sway control brands pros and cons.