Trust me there's no problem using Ragni trowels, I have used an 11in carbon steel Ragni trowel for all my S&C work for the last 25 years apart from when wearing in a setting trowel. I've also used their stainless trowels but unfortunately they're not as good as they used to be but still fine for a newbie to learn with, although a Perma shape will seem easier, just spend a bit of time with an oil stone to shape the edges. Get the guy teaching at the course to help you with this. As for bucket, midget and margin trowels the Ragni will be fine. Any bucket trowel that is strong where the handle joins the blade is fine. My margin trowels cost me £2 each (Swan I think) and are perfect, why spend loads on expensive trowels that spend most of their lives buried at the bottom of a tool bag. Whichever kit you buy add the other item as you will need both.
Remember there's loads of snobbery where tools are concerned, my old man used to say "a decent spread will get a good finish using the edge of a corned beef tin if needed".