May I pls ask where are you getting these names from. I know of Rubra (the KP w/ the reddish stems) but have never heard it called Brazil. Don't know what it has to do w/ Brazil & I'd drop that name as Hoyas don't come from Brazil. Not sure they even grow there, tho' coincidentally I grew up there myself. Never heard of Snowball anything before. I suggest this is just folks being 'creative' w/ names.

I asked my supplier about the snowball, it’s a hybrid of KQ and Krinkle 8. I haven’t tracked down the answers on Rubra/ Rubra Brazil

According to what I have read, Rubra is just another name for the Krimson Princess. Rubra was also called "tri-color". Hope that helps on that.

Snowball is a cultivar, so it's name is Carnosa cv Snowball. Leaves will look much like a regular carnosa, but the flower will be different. Hence the "snowball". Here's a great write up. Probably more information than you wanted to know, but it is sort of interesting. Quite the character!

http://www.psthehoyan.com/psthehoyan4_4.htm