At what weight/specific fights did Roy reach his absolute peak?

Roy is regarded as p4p #1 when it comes to speed/athleticism... and before he dropped all that muscle and went back down to 175, he was also considered unbeatable from 160-175. He showed dazzling speed in each of those weight classes. However, what was his absolute peak? I believe Roy himself said his best weight was 168. Was this absolute peak in terms of speed AND power? And is there any fight or fights in particular that you could point to and say this is the very best version of Roy? At 168 Roy seemed to maintain the same crazy speed that he had at 160 while bringing more power. Despite the added weight he was still able to dish out huge combinations. While at at 175 he didn't seem quite as able to throw such big combinations. And in his fight with Ruiz he almost looked past prime compared to how he fought at 168.