Baby Big is also a manual lever. The Riviera's are spring levers, and once again seals are NOT available for the older groups which use 3 piston seals, hence the purpose of this thread. I had to modify seals I got from Zacconi. I checked the website you mentioned and checked every known supplier, and even Christopher Cara hasn't had seals for these groups in years and is still trying to source some.
Cheers.

So how do you like the shots you get from the riviera? How would you rate the spring strength?

A very anemic spring in comparison to my Brunella and Faemina. Still, I'm not doubting it's capability just yet. Only pulled two shots so far, one with old coffee for testing. Choked the machine with 14 grams. Will go coarser or try a lower dose. Any recommendations?

Magic elixir produced! The shot volumes are very low but the results are quite good. I definitely need more practice. Seems to like a lower dose, as I went down to 12.5 grams and the pour is still a bit slow, on a grind setting I would use for my Caravel or Brunella. Definitely no Crema Monster here!
Very pleased I was able to get this thing up and running.