Remember that sleep is extremely important for everyone, especially us neurodivergent folks. I would not recommend taking any stimulant past noon. Hell, I struggle with sleep as it is and I take my ADHD medication at 6 AM.
I have a feeling that you'll adjust quickly and need to up your dosage to get any effect. I find that my body adapts very quickly to medications, especially stimulants. Unfortunately, that means building a tolerance over time and requiring either a long break or upping my dosage.
I'm not a doctor, so I can't give you advice on dosage. I just wonder how you'll measure it.