The perfect Aneros for beginner?


Ive owned a aneros knock-off (Nexus Excel) and got really great P-waves from it after a few uses. Now i wanted to go the official route and bought a aneros progasm. I dont have any problems with insert it, but i wont get any involuntarys (i got them with the Nexus). Now ive read that it could be because the progasm is to big for me (so it doesnt move much). Now i want to try out. Now my question is: What is the perfect and most famous aneros model for a beginner. When i´m advanced i can use the progasm, but i think i´m not ready yet.