Which mode should I shoot in: 24p or 24pa?

I know that with a DVX, it is recommended to shoot in the "A" mode. What about the V1 for editing on a 24p timeline???

24p Timeline - shoot in 24pA
29.97 Timeline - shoot in 24p

Thanks. Do you happen to know if Vegas supports 24p timeline, and, if so, what settings do I use? There are 1080/24p settings for 1440x1080 and for 1920x1080. What do I use?