Cal football general manager Ron Rivera spent 30 minutes Friday with reporters, discussing a wide range of topics on the eve of the Bears’ spring game on Saturday afternoon. Here’s some of what he covered: On what he’s seen from Tosh Lupoi in his first spring as head coach: “I think it’s all very positive, I really do,” he said. “You look at the things he’s tried to establish. And the first thing, more than anything, is his culture. He’s got pillars that he’s building . . . he’s working with the players to make them understand how significant those things are for our success.” On how spring practice has informed his opinion on what the Bears will look like next season:  “It tells me we’re going to be better than we were last year. I believe that,” he said. “We had a good team last year. I do think this team is capable of being better." On what has caught his attention during spring practice:  “What I’ve seen is the overall organization and structure of practice and the tempo of practice.…