In my experience, hospital pharmacies tend to be really good for filling out stimulant prescriptions. The shortage issue basically comes down to Schedule-II quotas and those are generally set per-pharmacy based on patient volume vs. controlled substance fulfillments.

This unfortunately means that low-volume convenience pharmacies tend to hit their quota maximum rather easily. Hospital pharmacies on the other hand tend to get fewer visits related to chronic conditions (e.g.: ADD/ADHD) and obviously have way more patient volume than the average Walgreens, so they're a lot more likely to vend to you without putting up a big fight.