Looking for gearing change for LX504T


After Malossi 79cc and Multivar variator upgrade my sluggish Vespa LX50 4T now performs as i wanted to, but now I need somehow increase its max speed. Now I get 65 Km/h on straight road and 70 Km/h downhill and it looks like it cannot make more RPM. I'm thinking to change gearing but I'm not sure do I need this? Will it perform well?

P.S. Acceleration is nice. I had to put 8.5g rollers to make variator work right. I guess because of low RPM compare to 2T.