I don't really see how you're confused by it. Put your deck size, change the hand size to 4 (or 5 if you want the odds going second), put in the number of copies of the card you want to draw.
That's really about all there is to it. You can be a bit more creative (say, count as 6 copies because you're running 3 cards that can search the card you're looking for), but it isn't complicated.
I think so.
From what I see, having 3 copies of Shirainui Spirit Master means having 50.88% chance of having him in your starting deck.
So at the beginning of each match you have 1/2 chance of opening up with spirit master.
I also find this starting hand calculator confusing.
How is it possible that having 3 copies of the same card in a deck of 20 equals 51% chance to open with that card.
For example, 3 Magician Navigation means Amt = 3. I want at least 1, Min = 1. Since the maximum amount possible is 3 then Max = 3.
The result it returns is 50.88%.
17/20 (85%) chance that it's not the first card
16/19 (84.21%) that it's not the 2nd either
15/18 (83.33%) that it's not the 3rd either
14/17 (82.35%) that it's not the 4th either
Total chance: 0.85*0.8421*0.8333*0.8235 = 49.12% that it's not one of the first 4 cards you draw. In other words: 51.88% chance to draw it within the first 4 cards.
I don't understand how some people still complain that Dark Magician decks are not consistent enough when you have so much chance to have all the cards you need in your starting hand