I like many over the years have, and continue to want an increase some how to the amount of Dil we can refine in a 24 hour period.
Since its a life long change like the Zen character increase, and the zen bank slot or inventory slot increase, id pay $50 bucks for it. Others may not, or perhaps would find $25 more resonable. Just my 2 cents, and im sure there are many more that would pay some amount for this type of Zen item.
Perhaps the $$ is off, But as far as paying for "luck" chances verses a small increase, from a consumer point of view I would take the for sure thing all day long first.