i agree both of you ads1115 is to get good resolution .
i am not too concern about 5v max output . incase of less light intensity i need to little boost the pre amp signal to max .
example with less light pre amp out put will be very less then scale will be very small even with 16 bit range . i need the digital gain control by Post Amp & offset control . TL074 currently available here i will try with this or i will try with AD8605/8606.