¿How would you send a record to a label?

I always send full tracks via soundcloud in a separate, private set. No serious label is going to consider you if you send teasers. Providing a set also guarantees no-one can just download the tunes and spread them without going through a huge amount of trouble. You can also check plays this way which helps to see how your tracks are received. I also make sure to make a separate set for each label or person I send it to.

The best advice I can give you is to follow the submission guidelines of the label closely! If they ask for Mp3 via wetransfer you have no choice basically and you have to assume they're going to treat your tracks with dignity and respect. Another suggestion is to not just try labels that have had a good run of releases/artists but also look closely at how the labels actually promote their music. IMO a label with a good track record but bad promotion is trumped by a relatively unknown label with good promotion.

Personally: Presentation is key. If someone sends me something in shortened English "hi d00d luk at dis will u" or overly obnoxious exclamations and smileys I won't even look at it.
On the leaked front: I don't know a single label owner in the scene disrespectful enough to do that, nor do I think any labels outside would be as bold. Some labels DO have stipulations in their FAQs about demos being sent in being used for promotional purposes though, but these are few and far between, and if they DO do this they'd make it clear somewhere so just give it a quick double check.
Also, I think small selection is a good idea, in fact, if a SINGLE song, if its good enough, will peak interest. Again though, I agree with VD, don't send teasers.

Just an observation, but if you've already gone to the trouble of paying for all of that yourself you'll get a lot more money back doing it all yourself than letting the label take a huge chunk for doing nothing other than "putting it out".

If you're adamant you want to do it through a label for whatever possible reason (under potentially false pretenses of exposure or promotion) then considering they'll have next to nothing to lose from gaining the rights to your music, make sure they push it flopping hard!!

+1

No worries mate, it didnt sounded bad at all.
And I completely agree, I simply cant understand paying for downloads more than a few euros. I like having something I can grab with my hands, lend to a friend or resell at ebay at absurd prices. Our first record were like that!

Is that one of those floppy-vinyl records that plays twice and then sounds like cottonballs thereafter?