As shown below, your pride is the only reason that post isn't helpful. It's just the plain truth, and one of the qualities of a good teacher is the ability to speak frankly, when necessary. Fish, or cut bait.
If you want to practice on the cheap, you can use a Clipper for this purpose. It's fairly large, and getting confident with it at higher-than-optimal speeds through the mail slot should be adequate preparation for the larger ships.
I don't agree at all with making any of the larger ships an option in any of the tutorials - part of the experience of those ships is the excitement and achievement of finally getting one, and flying/landing/docking them well is a next step in progression for a lot of pilots who should be fairly seasoned by the time they get one. The ability to muck around in them the moment you buy the game removes all of that entirely.
Also, the rebuy is part of the risk for even sitting in the pilot's chair in all ships. In the larger ships, the risk is substantially higher. If you are not confident enough to accept the risk of launching your brand new large ship, and flying it out of a mail slot (let alone doing any activity that carries higher risk than that), then the fact of the matter is that you aren't ready to buy one yet. There is no shame in this, get there when you are ready, and don't worry about what anyone else says or thinks.
You haven't said one way or the other, but the mail slot really is the least of your concerns. If I were you, I would be more concerned about my skill with the Interdiction mini-game, my piloting skill on worlds >1g, my ability in Combat, and my ability to generate income/recover from large losses, than anything else when it comes to flying the large ships. If you have shields at all, the mail slot really just isn't that much of a danger, and certainly does not need a tutorial option.
Edit: Here is something that might assuage some of your concern:
https://www.youtube.com/watch?v=LRYWlezRLE4
Riôt