The 7.9 gallon bucket will work for about 90% of the kits out there. Just get one and unless you get a kit that others warn about, you should be good.
Now as far as those two kits, I can speak for the Mosti Renaissance Amarone - it is about as good as you are going to get in a wine that you can start drinking in a few months and will peak in a year. The other one is no more sweet- both being a sweetness of 1- and needs 6 months to be drinkable. It also doesn't peak for 2-3 years. I would go with the Amarone myself, but that's just me speaking (because I love that batch).
If you are going to learn to like wine and develop a taste for it, you can't go wrong with learning on this one. You won't mistake it for a cheap jug wine!