How do I PROPERLY slow down a 60 fps clip in Vegas Pro 11? Let me start at the very beginning:

My project frame rate is 23.976 fps (standard film). When I create such a project in Adobe Premiere and then want to add a clip to the timeline, I can set the frame rate of the clip manually. Therefore, when my clip is 60 fps shot with a Canon DSLr (actually I believe and hope it's 59.94 fps), I can override its fps to 23.976 and then drop it to the timeline, thus getting the perfect slow-motion = as slow as possible without any frames missing in-between.

Now, I don't know how do I do this in Vegas Pro 11. All I can do is drop the clip to the time-line and then set its playback rate to 0.4x original speed (59.94 * 0.4 = 23.976). However, I don't know how safe this is. Is it safe to assume that the playback speed of the clip will be EXACTLY 23.976 fps and there won't be any frames missing in-between, thus creating the perfect slow-motion?
You should be safe setting playback rate at 0.400. 59.94 is actually 60/1.001 and 23.976 is actually 24/1.001, so the 0.4 multiplier is technically exact. Switch off resample to be sure. Of course, how Vegas actually handles this internally is anybody's guess.

One way to test this would be to generate a frame sequence just containing an incremental numeral display (1,2,3...) in AE or similar, then render that as a 59.94p video. Import in vegas with playback 0.4 and resample off and then cycle through the frames to see if there are any duplicates or missing.