Since you cited Evan Parker as your sound model, I spent some time listening to some of his music. Having done that, I wonder why you are looking specifically for a Berg Larsen mouthpice. I would not consider those to be appropriate for a beginning player.
Mr. Parker’s music seems to rely heavily on advanced saxophonic technique, but it is obvious he is a skilled saxophonist. So since you are beginning your saxophone journey I strongly recommend that you pursue a more conventional sound, using a more or less conventional mouthpiece. A Link Tone Edge, or Meyer, or Vandoren mouthpiece would be a good solid choice. The new Links and Meyers are excellent, and not too expensive. Vandorens are a bit more but are also generally made very well.
Once you get a solid footing in standard technique you can branch out into the more advanced realms that Evan Parker employs. A good quality mouthpiece of any type should accommodate those sonic explorations.