The only time you ever need “best” is when doing frame rate conversions, or when using higher than 720×480 source material.
Vegas is very slow at rendering. In your case — changing a widescreen project to 4:3 is a re-render of the entire project.
Other softwares can take the same file and send to tape without any rendering. I often use Vegas to render out single files, then print to tape using something else. I’ve never understood why Vegas still does the whole render to W64 audio of the whole project before a print to tape.
Let’s hope that Vegas begins to catch up with their competitors in this area. Print to tape and Text Creation are very, very weak. Maybe these will someday get the depth of the rest of this program. Until then — we just have to deal with excruciatingly long renders.
Byron Taylor