For G's sake, don't use Nero or Alcohol; pretty much a coaster if you do.
The best methodology is the pgcedit/imgburn system; it allows you to choose/specify where the layerbreak occurs, or default to the original. The ONLY decent commercial s/w to burn dvd9's is GEAR s/w, if you already own it (is the big competitor to Nero). But I've been using the pgcedit/imgburn freeware for well over 3+ years. The PGCedit site has a section devoted to DVD9 burning, almost required reading.
Best blanks by far are Verbatim (DL+R), most everything else is a crap shoot. They do tend to be the most coin, but I can usually get them at around $1.50 or less if I watch the sales and such at the major places (in the US, Meritline and Supermedia).
Of course, the best editing pgm (to get out all the crud) is dvdremake, but I figure you already know that; the freeware alternatives are there, and do work, but nowhere near as easy or fast to use.