I've had a few people trying to use the replacement New/Edit list form hack I posted a week or two ago, and struggling to get the correct set of fields to display so I've written a couple of followup wiki entries:

• Determining visible fields (shows a method for determining which fields should be visible)
  
• Configuration of fields (ordering, visibility etc. of fields) via an XML file.

Hopefully these will prove useful for anyone trying to make use of these hacks, and provide enough hints to implement something functional with the code snippets.