Is it Islamically permissible for a portion of the rent to be 10% of the project's income, and would that be considered gharar (excessive uncertainty/risk)?

"Leasing what is permissible to lease for a rent that is a percentage of its produce is a matter of scholarly disagreement. The majority of scholars (Malik, Al-Shafi'i, and Abu Hanifa) prohibited it due to uncertainty (gharar) and ambiguity (jahalah), while the Hanbalis permitted it by analogy with Mudarabah (profit-sharing), Muzara'ah (sharecropping), and Musaqaah (irrigation contract). There is also a narration from the Hanbalis permitting the combination of a fixed amount and a percentage of the income, although the correct view according to Ibn Qudamah is that this is not permissible. The preponderant view is that it is not permissible for the rent, or part of it, to be a percentage of theased asset's income, and this is the opinion of the majority of scholars."