What size milossi rollers do i need ?

Hi guys! For all u experts out there! Could anybody answer this question! I have 2005 aerox scooter I have a 70cc big bore kit,gionelli shot exhaust, the jet has been drilled to 68 to 70 in size! Need to know what size & weight the milossi rollers need to be? To get good speed when im cruising! dont care to much about the take off! any answers would much appreciate it