Rogerio,
Here's how I approach getting the vent holes lined up. There's more than one way to do this, of course, but I'll try to describe what works for me.
Before I start, I'd like to note that part of the trick is in having two places to tune: the placement of both the crook and the leadpipe. I know people who push the crook all the way in and try to do most of their tuning with the leadpipe. This is especially true for those who pull the crook often to empty the water and don't want to have to worry about repositioning the crook when time is short. I usually have my crook position pulled out just a bit, in case I need to adjust there. It also happens to optimize hole placements on my trumpet. Do whatever works for you.
It's probably easiest to start with the crook all the way in and all of the holes covered. Make sure you are using the leadpipe intended for the crook that's in place and that the screw plugs are in the same position for each of the hole pairs.
- Play a C'' (third space C) and adjust the leadpipe position so that it's in tune.
- Now open the hole used for C, the one under your ring finger or pinky and continue to play straight down the tube without compensating for any change in note color caused by opening the hole. If the pitch stays the same then that hole is placed properly. If it's sharper, you need to move the hole further toward the bell by pulling the crook out a bit (which will require a corresponding adjustment of the leadpipe being pushed in slightly). If it's flatter, the hole needs to move closer to the mouthpiece, which if the crook is all the way in may require you to move the screws to cover the other pair of holes on the top side of the crook.
- Once you get the C where it should be, check the E, G, and high C. They should now be in tune as well, provided the mouthpiece is a good match for you and the instrument. You might need to compromise a little and adjust the position to get the note you care most about closer than the others, but you get the idea.
- Now check the index finger hole. If it's in the right position, the F# should be fairly well in tune. Although I will say that it is a little flat on every Egger trumpet I've ever played. This helps when it's the third of the chord but makes leading tone F#s a bit more of a challenge. Such is life with the baroque trumpet. The F# should now be in a place where you can lip it to make both the thirds and leading tones work.
- Finally, check the F and A with the thumb hole. The larger size of the thumb hole tends to make them more bendable, so I tune them last. Usually they are OK, but if they are really out of tune, you may need to shift the screw plugs to the other set of holes and start the process again.
It probably won't be possible to optimize the hole positions for all notes that require venting. Aim for the best set of compromises.
Let me know if these steps don't work for you and I'll do my best to help you figure out what to change. Best wishes.