*SPOILERS* After playing the game repetitively for background differences and achievements, I'm pretty convinced the result bar is kinda random except for a few instances. It's important to remember its about relationship progression, as in, how much you find out? Instead of how well you treat Asterion?
This is mostly speculation as I've observed that some of the "nicer" responses don't yield a better score, say for rubbing the wine in for him. I believe events like revealing Jean as Hermes or revealing Argos as Dominikos as those things would reveal more about Asterion than having 2 different small dialogues. I don't think continuing Asterion's project increases the result bar. My first playthrough gave me Bronze Dragon, which was overall disappointing until I realized it was more about revealing the story. The highest I've ever gotten was Gold Wolf.
Overall, the result bar is very misleading and should be taken out of the game to avoid discouraging players going through their first playthroughs, but I understand its importance for the Devs at the survey polls. Although, I think it's fair to assume most players won't discover Hermes, and ~40% would reveal Dominikos since translating the pages is relatively easy (10 Contract). Even though I did not do it because I thought it would be useless impact on the story like the tablets.