Delta Velorum - non-observed variable star I am a beginner variable star observer from the Southern Hemisphere (but with experience in astronomy) and, when I was looking for VS to observe, I saw that Del Vel has almost no observations. Thus, there is no graph for when the eclipses occur.
VSX data: mag range of 1.95 - 2.43 V, period  of 45.15 days and 1.3% (0.587 days) eclipse duration
It doesn't have data about how the magnitude varies in the visual spectrum, althought I know it is a bright star (already saw it at naked eye).
Does it vary in the visual spectum, or there simply is no data enough to determine this? Could I collect this information visually, or is this waste of time?
Yes it varies in the visible spectrum.
The paper  The nearby eclipsing stellar system δ Velorum describes why this is difficult target.  Surprisingly it is because it is so bright.
The absolute brightness of a star will vary significantly due to absorbtion in the atmosphere.  If the sky is slightly hazy, then the stars will be dimmer.  To measure the magnitude of a star, then, you don't directly measure how much light is coming from it, but compare it to nearby stars.  But δ Velorum is one of the brighter stars in the sky, so there are fewer nearby comparison stars.  This, combined with the long period of the orbit makes observations harder. This probably explains the shortage of observations.